Making BP .45s work in long gunz

[Cuts Crooked]

There have been questions about using BP in the .45 Colt in long guns periodically, the most recent concerning their use in trombone gunz (lightenings). I wrote the following for The Cowboy Chronical some time back (actually this is an early draft, I cain't find my final submission as printed ) and I think it is pertinant to the use of BP .45s in any long gun.

Fact is, Americans have been enamoured of having rifle and hand gunz chambered for the same round for a long time. It made sense 150 years ago and it still does today, and for much the same reasons, ease of reloading, simplifying purchase of ammo/componants, and yes...even when things go really bad and one finds oneself down to one gun in a bad situation. In our game it also makes sense to have both gunz chambered fer the same round fer another reason..when it's time to do a fast reload on the line it's a major help not to have to stop and think to ones self, "do I have the right ammo!?!?!"

But...when Colt designed the .45 they weren't thinking about about long gunz! They were designing the round to be used in their fabulous single action revolver! And because of that, the case they originally designed had a tiny little rim on it, unsuited fer use in a gun that used a single point mechanical extractor to yank the cartridge out of the chamber.

Time passed, things changed in manufacturing and the .45 ended up with a fairly substantial rim on it. And some bright boys in the sales departments remembered Americans love for having pistols and rifles chambered in the same calibers. And we began to see reproduction lever guns chambered for the mighty .45. They worked pretty good with that new fangled smokeless powder too!...More time passed and some crazy Cowboy Action Shooters decided they wanted to shoot these new lever guns with black powder, similar to the original loadings...and I wrote the following:

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The .45 Colt, Black Powder, and Lever Guns

Howdy Pards 'n Pardettes!

This article explains how I use neck sizing to improve the seal of the .45 Colt cartridges to reduce fouling caused by blowback. As many of you know, I shoot strictly in the frontier cartridge categories. A few months ago I bought a reproduction 92 Winchester chambered for .45 Colt. I was tickled to no end because I shoot .45 Remington revolvers as my main match guns and would like the same caliber for my rifle. The .45 doesn't have the best reputation in lever guns when loaded with the black stuff. In fact, the former owner said he was selling this one because black powder badly fouled the action. From what I've read on the SASS WIRE I understand that this is why .44-40 and .38-40 caliber lever guns are so popular, they don't allow as much blowback as the cartridges with straight walls.

I examined the gun when I received it and found it had a somewhat large chamber, which is probably one of the reasons the previous owner got so much fouling. All that open space around the chambered cartridge was letting a lot of powder gas blow back into the action! Having no experience with the .45 in lever guns, I approached this problem with a bit of concern. I've learned a few tricks from other SASS members about black powder in .45s and discovered one or two on my own. Now it was time to see if these would help me with this gun!

The first trip to the range established the gun was accurate!!! (I wish I could shoot standing on my hind legs, like I can off a bench rest! No one would have a chance against me!) But it did quickly foul the action! There was lot of nasty stuff getting in there! I used my standard revolver load: a 255 grain modified maxi ball seated over 32 grains of 3F with a card wad between the slug and the powder charge. The Maxi Balls had been modified to create a large meplat for safe use in a tubular magazine. With all of the fouling problems, I went back to the loading room to think about how to cure this problem.
Fellow Darkside shooters like Doc Shapiro, SASS #31526, have found that blowback can be reduced in the .45 Colt by using a heavy bullet with as much black powder as you can get in the case, and then using a small amount of compression. This lets pressure build for a millishake in the case before the bullet starts moving, thereby expanding the case into the chamber walls for a tighter seal.
I was already using a heavy slug and a stout powder load so I could not increase the load to better seal the cartridge to the chamber. What else could I do? I was looking at an old bullet chart on my shop wall and the picture of a .44-40 kept drawing my attention with its sleek bottle necked case. That's it! I simply needed to find a way to slightly taper a casing to better seal it against the chamber. I examined a few cleaned cases with a micrometer and compared them to my finished reloads.
There was a considerable difference b'twixt the case diameter of the fired casings and the full-length sized reloads. The reloads were much smaller. I figured I could set the depriming rod very low in the case-sizing die and remove the primer while only resizing the open end of the case. I put it back in the press and adjusted it so the depriming rod tip was level with the bottom of the shell holder when the ram is at the top of it's stroke. This left a large gap between the shell holder and the base of the die. I put a case in and ran it up into the die! I pulled out a deprimed and "necksized" .45 case that looked almost like a bottle necked case! This looked like it had possibilities so I prepared a hundred rounds and proceeded to reload them with my standard black powder combination.
After cleaning the action of the rifle, I went to the range for testing. One hundred shots later, I was very pleased! Accuracy was still excellent, the gun functioned perfectly, and there was hardly any blowback fouling in the action! The slight "shoulder" created by only necksizing the cases was enough to create a situation nearly identical to real bottle necked chambering. The rear of the case appears to fill the chamber completely and block the flow of gases back into the action. I later found these loads chamber in my Remington revolvers with a bit of a push instead of a simple drop into the chambers. The fit does not concern me in slightest!

If you want to shoot Black Powder in a lever gun chambered for .45 Colt, this appears to be a new alternative! Use a heavy bullet in the 250 - 255 grain range, "necksized" only cases, a full charge of slightly compressed powder, no fillers, a card wad over the charge, and a heavy crimp on the slug. This combination works great for me and I imagine it will for you other pards who are considering Black Powder in your .45 lever guns! Go try it! It's a BLAST, and that's what being a Darksider is all about! <grin>

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Since that was written I've learned a few more things that will make the .45 even better with BP in long guns!
Annealing: This makes a MAJOR improvement! The act of heating the neck area of the case to soften it slightly helps let the brass expand easier into the case walls and creates a better gas seal to prevent blow back. A word of warning here: I've seen several times on the net the recommendation to heat the necks until they glow cherry red. DON"T! Doing so will "burn" the brass and make it very brittle! It only needs to be heated until it just begins to change color. I heat mine with an LP torch, while holding the brass by the rim with a heavy pair of pliers, turning it constantly and then dropping it into a bucket of cool water to quench. Note: brass is not like iron & steel in that quenching it makes them hard!
Another major assit in using BP in the .45 is to find the thinnest brass you get your hands on! Winchester .45 brass seems to be the thinnest out there, with Star Line being the thickest. (nuthin wrong with Star Line it's jist really thick) I've also noticed that Winchester brass with the WW headstamp seems to be thinner than their brass that has the full word "Winchester" stamped on the case heads.

I will also add that I know that the above sounds like a major pain! It's a lot of time and effort to put into preperation, no question about that! But for me and many of us the steps to reload a properly functioning .45 BP round is kinda relaxing. And I guess it depends to some extent on how dedicated one is in making things work the way we want them too, in spite of the manufatures original design flaws!

Hope this is helpful to some of you pards who love that big old .45 round as much as I do!

[Lars]

I do something similar, which also works well, at least in my revolver. However, what I do and what Cuts describes above can cause one or more problems. Basically, it is a "one-gun" solution.

First and most obvious is that not all rifles and revolvers have oversize 45 Colt chambers of exactly the same diameters. It is common to find rifles, especially Marlins, that have much larger 45 Colt chambers than do Rugers, etc.. This can lead to a nasty case of just the problem that Cuts' approach would avoid, that is, getting a round that will not chamber in a given gun, at the worst possible time. One can even end up in the worst possible situation, with 3 different 45 Colt ammos that will each only fit into one gun (and that assumes that all 45 Colt chambers in each revolver are the same). In the hand, these different ammos are so identical as to be a nifty trap for the less than totally organized shooter.

To avoid the above I have minimially resized my 45 Colt ammo to fit the gun with smallest chamber(s). In my case that was almost the same as totally full-length resizing everything.

Perhaps not so common or so obvious is that some guns have chambers that are not perfectly round, they are slightly oval. In this case, full length resizing is essential.

What I do.
While I don't and won't have a rifle chambered for 45 Colt, I do use a 45 Colt Ruger for some of my BP shooting. Fortunately, it has 6 identical chambers, that is, the case from a round fired in any of the chambers will fit into any of the other five chambers as well as in the chamber in which it was fired.

Thanks to this happy situation, I never resize the brass. This does create another problem. One needs oversize, soft lead bullets that fit snugly into the unresized case. For this I use 0,457 pure lead roundballs. Keep intending to try Remington 0,455 pure lead 255 grain bullets, or some custom made ones at 0,457 to 0,460, but, have not yet. The load I use is really just my 44 C&B load in a 45 Colt case. It is a volume of 777 FFg somewhere between 22 and 30 grains, 1/2 of a 0,460 X 3/8 inch lubed fiber wad from Circle Fly, the 0,457 ball, crimping is done normally over the RB. No surprise, down range performance is same as from a 44 C&B -- totally adequate for CAS and recoil is similar, as it should be.

I find that blow back of BP powder fouling is minimal with new 45 Colt cases (that softer, not-yet-work-hardened brass that Cuts notes) and increases as the cases are used. Also, the more powder, the less the blowback, everything else being the same (especially case hardness).

What I also did for a while was expanded 44-40 brass to 45 Colt diameter and loaded as above. This worked much better because of the thinner brass of the 44-40. However, since I shoot 44-40 in all my other guns, I was setting myself up for some real tight jams when a 45-40 got into my 44-40 rifle.

Lars

[Dakota Widowmaker]

The only brass thinner than W-W is 44-40 brass.

Some pards have decided to shoot that instead after resizing it. (which seams extreme)

A good way to "bulk" aneal brass is to put it in a gas grill or oven at least 600 degrees for an hour or so.

The melting point for brass is around 1650F. Annealing usually takes place at a much lower temp. (600-800 for most alloys)

My metalurgy book from college states it at 800F, but, I believe cartridge brass is at a lower point.

Here is an article that talks about it more...
http://www.lasc.us/ConversionTables.htm

I like their "bases in watter" method, but, again, running a torch over it till its glowing is BAD.

The single most prefered method I have seen so far is to use fire formed cases and only neck size them when loading.
(Lyman 310 dies are GREAT for this...)

[Bad Flynch]

C.C.--Everything you say is pretty darn goog advice, I'd say. However, I ended up rebarreling and rechambering my 1894 CBC to .38-40. It is like the rifle was born to be just that. No more blowby, with case necks clean, even. Feeds and functions exceedingly well. I recommend it after all else is less than perfect.

[Cuts Crooked]

Ok.....

Pards, I started this just to help pards who want to shoot BP in their .45 long gunz. Most of us know how well those grand old bottle necked cartridges work in them...they are simply fabulous, no question! But , for better or worse, the manufactures have brought out a lot of guns in .45 and a lot of Cowboy shooters have them. For various reasons, they choose to stick with them, even when they get bitten by the Darkside Bug. The plan here is to help those shooters!

A couple of you have brought up those great old cartridges so I will mention something else that I encountered, to save others some problems. One of the tricks I tried and discarded over the years was to use 44-40 brass, necked up for .45s. This worked fine in my revolvers but they wouldn't work in my Rossi! The difference in case head dimensions was just enough that they would not chamber in the Rossi due to the bolt face & extractor being cut jist a scootch smaller for the .45. I understand that they will work in SOME rifles though, it's a hit & miss solution so to speak. (pun intended  )
Two pards I know that have had their lever guns rebarreled, one for 44-40 and the other for 38-40, found that they had to take them back and have the bolt faces reworked, at added expense, in order to chamber those rounds. Another had his .45 bolt reworked so that he could use 44-40 brass but kept his .45 barrel. That worked great for him but it resulted in another problem. When some standard .45 cases ended up in his rifle they would not extract! The changes in the bolt face and extractor, needed to make it work with 44-40 brass, also made it unable to get a good grip on the tinier .45 rim. Again, it's a hit & miss thing that varies from one gun to another, but it's something to keep in mind when searching for a solution.

I might add here (yes I'm bragging, ok?) that I won the 2003 state championship here...with that old Rossi .45 of mine, loaded with BP!  So I know that .45 in long guns is doable!  

[Dick Dastardly]

Ho Cuts,

I know you've heard this before, but I'll bring it up here cuz it may help with the 45 Colt rifle blowback conundrum.

Silas McFee n' me shoot 44Magnum 92s.  Mine are Brownings, his is a Rossi.  The 44 Magnum is a stout straightwall case.  We shoot full house warthog loads of Holy Black under Big Lube^tm Mav Dutchman boolits.  We don't get all that dreaded blowback in our rifles.  We easily go a ten or twelve stage plus side matches yearly shoot without need to clean to maintain function or accuracy.  I've even shot long range pistol caliber rifle side matches with great success after shooting the entire two day main match with no cleaning.

I'm forced to ask if 44 Magnum brass, we don't sort by maker, is thinner or seals better than 45 Colt brass???  We don't have the problem of blowback in our guns and I've not heard of any other shooters shooting this caliber with Genuine Powder having blowback problems.  Are the chambers for 44 Magnum that much more precisely specified and machined?  Whatever the reason, we just don't have blowback problems.  Silas shoots a lot of 44 Special ammo in his 92 and still no blowback problem.

I would suggest that whatever is happening with our straight wall cases that were definately NOT developed with Holy Black in mind might be employed successfully to help keep the 45 Colt rifles' insides clean.

I'm NOT throwin' water on the 45 Colt campfire here, just ponderin' an apparent contradiction that ought not to  exist.

Also, going down in caliber, why does not the 38 Spl/357 Magnum case seem to give all the blowback problems with Holy Black?  I  have a Browning 92 in 357 Magnum and shoot 38 Special brass stuffed with all the FFFg I kin get under a Snakebite Big Lube^tm boolit.  I  have NO blowback problems whatsomever with it.

I'm tryin' to help find a solution here.  I'm not tryin' to start a wild fire about calibers.

Love the smoke!

DD-DLoS

[Cuts Crooked]

Howdy DD,

I'm not sure, it may be attributable to several factors, including heavier brass. One thing you mentioned that I think may have a bearing on it is that the .44 Mag, being a more recent introduction, may actually be be subject to tighter tolorances in machining. It is after all intended to be a relatively high pressure round from the outset and manufactures may be holding the chamber specs tighter because of that. The old .45 on the other hand was originally intended as a low pressure revolver round and as such the chamber specs invented by Colt were probably a bit on the loose side to allow for that and the fouling that went with BP. In a revolver, with its rod type ejector and little concern about blow back getting into the action, this worked fine for Colt...a little "slop" in the chambers was no problem. In fact it probably made it easier to manufacture a multi chamber firearm that way. Maxi chambers with Mini brass! Then too, the original loads were made with much softer brass...even copper... they probably sealed the chambers better than the stuff we have today. I know this fer certain though: Factory loads and full length resized reloads "rattle" in the chambers of my revolvers and my Rossi.

So, what we probably have is manufactures making these guns to original specs, combined with heavier brass than the originals!?!?! I'm jist throwin out thoughts here, no facts to prove it!

I find it interesting that no one reports problems with the 38s too. I have just the opposite problem!!! My .357 Rossi is not terrible with BP, but it's not as good as I'd like concerning blowback with BP. I've never actually checked the chamber in it but I suspect that my particular .357 is a bit loose. Anyway, the same things that helped resolve this in my .45 Rossi work with it....heavy slugs+ full powder charge+ "necksized"  & annealed brass = no fouling getting into the action! 

[Dick Dastardly]

Thanks Cuts,

Let's go with the tighter tolerances for the 44 Magnum.  Even though it wasn't introduced with BP in mind, it makes a great BP cartridge.  That may be because the parent cartridge was the 44 Special, and that's a fine BP cartridge.

I'm thinkn' you're on to somethin with the chamber specs.  Were I to have a "dirty" 45 Colt rifle, I'd be mighty tempted to have a custom die made that would size the brass just rite for that gun.  Huntington Die Specialists would be a good place to start looking.

Also, I'm thinkn' that reduced loads in the mighty 45 Colt hull could be a bit of a problem.  Plenty of pressure is needed pronto to expand that hull out tight to the chamber wall and prevent any gas from crawlin' back around and into the gun.  I'd even be tempted to give FFFg a go.

DD-DLoS

[Lars]

Cuts,

There is one thing that has crossed the minds of several of us, but we never pursued it cause we have 44-40s. Your comments about the bolt face and extractors problem with 45 Colt Marlins reworked to 44-40 or used with 45-40 caused me to remember this.

Given that part of the problem with modern 45 Colt guns and BP is the commonly overly large chambers, it would seem logical to have the rifles rechambered to absolutely minimum 45 Colt chamber dimensions, maybe even smaller. The user might have some issues with needing custom full lenght resizing dies with smaller than minimum SAMMI chamber dimensions. Actually, from some limited personal experience, I would expect custom resizing die to be an essential part of the total solution, carefully mated with chamber dimensions below SAMMI dimensions. (Anyone know the chamber dimensions on Freedom Arms 45 Colts, or other high precision revolvers?)

I strongly suspect that little experience is out there with this apparent solution, at least for use with BP. Feeding might be the first problem encontered, as it is often with match-dimensioned chambers on other guns using straight walled cases.

Actually, going to custom chambers and loading dies offers to make a special BP varient of the 45 Colt, one with slightly tapered cases, as well as mimimum differences in dimensions between chambers and resized ammo. Might even make a decent BP rifle out of an old revolver cartridge. Might call it the 45-T-Colt. NOW THAT would be using the classical, ancient solution to designing BP rifle cartridges.

Getting chamber dimensions down into the realm of match chambers should result in smaller groups. Anytime the ammo rattles around in the chambers, small groups are sorta in the realm of accidents.

Still another solution would be for someone like Starline to produce a line of 45 Colt cases designed for use with BP. Basic feature of such brass would be its softness and resistance to work hardening.

I really go serious doubts about how much diddling around with sloppy dimensioned guns and ammo made from modern brass will solve this.

Lars

[Dick Dastardly]

Hot dang Lars,

I like your plan.  Make the chambers to minimum SAAMI standards.  I like that.  I also like the idea of naming it the 45 T Colt or some such.  It's the child of the Darkside and ought to bear the mark of the Darkside.  Dare I suggest the 45 D Colt?  It's not mine to invent, but to listen and learn.

Lars and I have pulled at opposite ends of the rope from time to time, and we may well continue to do so.  However, if his solution works, I and many others will benefit from his wisdom.

How much does it cost to re-chamber a sloppy chamber rifle and then re-ream it to SAAMI minimums?  I'm thinkn' that if the problem of soot blowback is a widespread problem there might be a good smithy that will take this modification upon himself.  Then, since a tight carbide sizing die would be needed, a manufacturer found to supply said same at a very fair price depending upon demand.

Hey, there's learnin' goin' on here. . .

DD-DLoS

[REELFOOT REGULATOR]

Here is my thought on this. I shoot a Rossi 92 in 45 cal. I use the 200 gr big lube bullet with a light charge of 20 gr of 2fg. Yes i do get alot of fouling in the action, but the rifle still functions flawlessly through a whole day of shooting without cleaning. i really have not explored any of the methods dicussed here, because the gun works regardless.

[Lars]

Well, the 45 Colt is already a BP load, just a revolver not rifle cartridge. Would seem a bit redundant, even ignorant, to suggest once again that it is a BP cartridge. Might be more accurate to call it "45 Colt-Rifle". I am sure that the the folks using nitro would benefit from it too, given the often sloppy groups and incessant blowback common to 45 Colt rifles.

One more or less common method of redoing chambers on old rifles, ones that have suffered lots of corrosion over the decades, is to ream out the chamber and put an insert in, then cut the new chamber in the insert. This is a neat way to preserve the outside of an old rifle. Have no idea of the relative costs of setting back the barrel and rechambering, cutting new extractor slot(s), etc. compared to the insert and rechambering method.

Lars

[Dakota Widowmaker]

Just to add (again)

Fire forming cases and only neck sizing is very much a "standard procedure" for many soot lords.

I have found that the chamber in my Henry for 44-40 is VERY close to factory specs, so, I just neck size.

If you have a chamber on a rifle that is "on the high side" of specs, meaning, fired brass can't be just neck sized to fit your revolvers, then having a new chamber cut and the mag tube shortened just a tad is not unheard of.

A good chamber, fire formed brass, and a solid roll crimp have been my salvation with my 38-55 and not having blowback.

I have no rifle that shoots 45LC, but, I am glad to see that these issues can be overcome.

I am now the proud owner of a new Win94 Trapper in 45lc. Price was right and I wanted a rifle to match my six guns.

[Griff]

I think Dick touched on the true answer... 3F.  I've been shootin BP since '87 and after trying all the synthetic BPs, I found that 3F in my .45 Colt Uberti '73 rifle gives fine performance.  Ya, sure, there's a some fouling in the lifter after several stages, but I can easily get thru 6-7 stages w/o cleanin.  I generally load 25-28 grs (wt.) under the RCBS .45-225-CAV bullet and crimp heavily.
Heck, my $0.02:  If BP were easy, then everybody'd be doin' it, and then I couldn't be the only one stinkin' the range up and generally agravatin' the yokels!   Though it is funnest when there's at least 1 BP shooter in each posse, to help spread the joy around

[Lars]

Griff,

I strongly suspect that the most important factor with your 45 Colt chambered rifle is that the chamber is not so badly oversize as is common for this caliber. For my some 45 Colt chambered gun, a Ruger Vaquero, I never resize the brass and get much reduced powder fouling back along the cases, compared with same cases full-length resized. Same result no matter what the powder.

Lars

[Griff]

Lars:  maybe so, maybe so.  I find that if I use a "dirty" smokeless (ain't really any such thing is there?) I get just as much fouling in the lifter of my '73 as when I'm shooting BP.  In fact, at a recent match, I used some loads that had been around for several years, and I didn't get through all 6 stages without having to spray some Gunk around the lifter to remove some fouling.  These were not BP loads, but were loaded so long ago that I don't really know what powder was in them

[Lars]

Griff,

Your experience with "dirty" nitro loads in 45 Colt is not uncommon, actually, I see it a lot. For example, recently we borrowed a Rossi 92 in 45 Colt. The gun had been used heavily with Unique standard "cowboy" loads of 200 grain bullets and 6-7 grains powder and the innards seldom cleaned. IT WAS FILTHY INSIDE!! A toggle-link would likely have long since gummed up. The innards of my 44-40 chambered Rossi 92 have not been cleaned for maybe two years of monthly use with BP loads and are far, far cleaner. The difference is simply that the thin 44-40 brass obturates fully and no powder gases get back into the action. It is important that the 44-40 round was designed for use in rifles, whereas, the 45 Colt was a revolver cartridge that was never designed for rifles.

One can readily conclude that use of the clean-burning, fast-burning shotgun powders, designed to not clogg up the innards of autoloading shotguns, is the best way to go with 45 Colt in rifles for CAS use. You and others seem to have learned this.

What I write below is intended to be useful to some reader or other, if not to you, perhaps to someone else.

The two big reasons some of us do not like 45 Colt cartridge for low pressure (about 8.000 psi or less chamber pressure) loads, nitro or BP, are the thick, tough brass used in modern 45 Colt cases and the often too large chambers (for easier feeding? because of "sloppy" SAMMI standards?). This leads to a lot of powder gasses blowing back past the case and getting into the innards of rifles. Again, this was a revolver cartridge that was never designed for rifles. Modern 45 Colt hulls do have slightly larger rims for use in rifles. 45 Colt brass is also the same brass as used in modern cartridges, like the 44 Mag, that generate far higher pressures. Load the 45 Colt to pressures well above SAMMI (NOT for use in Colts, Colt replicas, toggle-link rifles, or anything other than Rugers, Rossis, modern Marlins) then the modern 45 Colt brass obturates nicely, just like it does in 44 Mag.

Down at BP pressures, wheither produced by BP or nitro powders, one has to go to extraordinary measures to reduce powder gasses from blowing past the poorly obturated cases. There are several ways to reduce this blowby, none are fully satisfactory. Most or all have already been mentioned in this thread. To list them: 1) don't resize the brass at all, 2) neck size just enough to hold the bullet, 3) use 250 grain bullets (especially soft, even pure Pb), 4) use a good soft fiber wad to give reliable sealing behind the bullet, 5) push chamber pressures well above 8.000 psi (about the minimum chamber pressure to obturate NEW 45 Colt brass) -- almost none of the recommended "cowboy" loads exceed this pressure by much -- SAAMI max recommended chamber pressures are about 13.000 psi, 6) anneal the upper 1/2 of the brass. ALL of these will reduce the blowby some, maybe even a lot. I use #1) and #4) and oversize (0,457-0,460) pure lead bullets for CAS -- I get greatly reduced blowby, but still more than I would tolerate in a rifle or get with 44-40. For non-CAS I load 45 Colt to SAMMI or higher chamber pressures (Ruger Vaquero usage) and get nearly no blowby and even that is limited to the top cm or less of the case -- IF I am using new brass. Brass work hardens with reloading and the blowby will increase after a few loadings.

Lars

[john boy]

Cuts:
* ... I don't neck size any of my 45's
* ... I don't use any wads
* ... I don't get much blow back

I do use a 454 bullet, only BP in the case and a Lee Factory Carbide Die crimp.  I find the same is true (minimal blowback) with 459 bullets in 45-70 cases too - black powder only

[Dick Dastardly]

One thing seems to be a true and common thread in straight wall cases.  They need enough pressure quick enough to expand against the chamber wall.  I've seen cases actually folded in on themselves from blowback in extreme low pressure loads.  Usually this kind of thing happens with bottleneck cases though.

When ignition starts, and before the bullet starts to move, is when cases need to expand.  Brass is great for this.  It also contracts enough after fireing to allow easy extraction if the pressure was within limits on the tall end.

When the brass does expand quickly and fill the chamber, blowback is usually not a problem.

The remedy for many blowback problems is softening the brass neck.  Properly done by annealing, this makes the expansion of the case out to the chamber wall happen at a lower pressure.  Another remedy is to keep the ammunition close to chamber dimensions so the brass doesn't have to stretch as far.  A third and sometimes overlooked remedy is to use a powder charge that will burn quickly in order to get the case expansion going before the bullet starts to move.

Strait case cartridges lack the bottleneck that helps build pressure in rifle cartridges.  For this reason, usually faster powders are used in straight wall pistol cargridges than are in bottle neck rifle cartridges.  There are many other internal ballistic factors that come into play with powder choice, but this handles the basics.

Since the 45 Colt cartridge has the versatility of using both FFFg and FFg I'd use the finer grained FFFg powder if case obturation/blowback were a question.  Also, a case full of compressed black powder will generally build more pressure quicker than one filled 2/3 full and the fill completed with fillers.  Fillers tend to compress upon ignition and take some of the shock out of the first stages of the burn that may be needed to expand the case.  In other words, they act somewhat like a shock absorber, discipating the whack needed to expand the case immediately.

Once blowback starts, hot gasses begin to exit out of the chamber back past the cartridge case instead of pushing the bullet up the barrel.  Several bad things happen at this point.  First of all, hot gas is going backwards.  That's the direction towards the shooters eye.  Second, energy is being wasted that ought to be used to move the bullet along up the barrel.  Since blowback is seldom uniform from shot to shot, the venting gas going back towards the shooters eye varies from shot to shot.  This means he may, or may not loose an eye on any particular instance of gas jetting.  It also means that his bullets are going to exit his gun at varying velocities depending on how much gas went forward, and how much went back.

So, all in all it's in the best interest of the shooter if all the hot gas pushes the bullet up the barrel and out.

DD-DLoS

[Snapshot]

Howdy Cuts and all who shoots the delishuous black powder.

I shoot a 73, 45cal. 24"Uberti replica Winchester rifle, Been using it for years. All beaten up by now. I recognice lots of the loading prosedure ya-all talk about. I am just missing out a minor but not unsignifcant part that I use in my loads. The cardboard wad that I use between powder and the 255grn. bullet. I soak the 12mm. cardboard wads in olive oil and air dry on a towel or an old rag. When I squeeze the wad after drying it still hold a signifcant amount of olive oil. This seem to help keep the barrel cleen and it seems like my rifle can keep on for at least ten stages with no hussel. Just shoot and hit, shoot and hit.!
My firm belief is that this primitive gas-check of cardboard and olive oil between the 255grn. and 32grns of FFFg does the diference. It helps keep`n the rifle woorking and it seem to help acuracy to.....!!!

Just tought ya-all chould know.