Tempature effect on chronographs??

[treebeard]

I have acquired a chronograph for testing velocity of my various reloads. I have never used one before and was curious on the effect of tempature on the velocities considering it is winter and here in south central Kansas i can only expect to have temps in the 40's and 50's for a while unless i get lucky and a good day shows up in the 60's. I reload for 25-20WCF Thru 44-40WCF, 45-70 and even 56-50 Spencer.

[Yeso Bill]

I'm in N.M. at an elevation of about 5,000 ft. and here we experience day to day extreme fluctuations in temperature.  (It is 68 and too windy too shoot now and might be 25 and calm tomorrow)  Wind permitting, I try and shoot daily and with our dry south west weather, I generally leave the Pact chronograph in place.  So, I rarely shoot without using it.  I have spent the last few years shooting the 44-40 rifle and keeping records of the temp, humidity and velocity. 

I would say, as a general rule of thumb, 10 degrees equals about 10 fps and whether BP, RL7 or H 4198, 1/10 of a grain equals about 10 fps.  Whether this holds true with other calibers, I can't say. 

Billy 

[treebeard]

I'm in N.M. at an elevation of about 5,000 ft. and here we experience day to day extreme fluctuations in temperature.  (It is 68 and too windy too shoot now and might be 25 and calm tomorrow)  Wind permitting, I try and shoot daily and with our dry south west weather, I generally leave the Pact chronograph in place.  So, I rarely shoot without using it.  I have spent the last few years shooting the 44-40 rifle and keeping records of the temp, humidity and velocity. 

I would say, as a general rule of thumb, 10 degrees equals about 10 fps and whether BP, RL7 or H 4198, 1/10 of a grain equals about 10 fps.

Billy

Yeso Bill--I assume that as temp goes up the FPS goes up? I agree on that wind permitting comment--I am originally from the Gulf Coast and many of the winds here would be considered gale force down there and the warning flags would be out!

[Yeso Bill]

Gale force?  I like that.  Nice sound.  I'm going to add that to my vocabulary.   

Yes.  As temperature goes up, so does velocity, which more importantly means....so did pressure.

What bugs me so much is my guns (Uberti's) shoot a heavier bullet best in the 1250s.  So, I'll go out and shoot some reloads the next day and they are in the 1220s, hitting low on the target.   I'm tempted to load 100 of each 1/10th of a grain apart, check the temperature and pick a box.  But, I haven't done that yet.   

So, I am hunting that sweet spot where the pressure won't be too high for the brass framer's on a warmer day but the velocity won't be too low on a colder day.  Sounds simple but it has been elusive. 

Billy

[Coffinmaker]

First a Disclaimer:  I have not spent a night at the Holiday Inn Express (That I admit) and I have never ever, over 50 years of play, owned Chronograph.  The last several Lustrum, I have shot BP and Subs exclusively.  I have no idea what the velocity(s) of my ammunition is or was.  I have found an amount of propellent that gives me a nice pleasant to shoot load, is accurate enough to reliably "Ring the Steel" and runs thru my 650. 

I am well aware (I CAN read) velocity will very with temperature and in fact some GAMEY loads that work just fine at 75F may well not even go Pfffit at 40F.  With BP and Subs that is a moot point.  BP and Subs always go BANG and the few FPS difference is academic.  Whom Cares??  Simply shoot enough that you know where the bullet goes in whatever weather, adapt and overcome. 

[Yeso Bill]

Coffinmaker,
      With all due respect, because I think highly of your posts with opinions and facts.  (I read everyone of your posts)  I care.  I set out several years ago to see if I could consistently hit the turkeys at 385 M. with the 44-40 and it has been a great learning experience.  Stretching the 44-40 out at longer distances and getting good tight groups isn't going to be hardly done without low SDs (10 and under) and a chronograph will get you there faster than none. 

Now personally, I don't really care how someone choses to enjoy their guns.  If they want to shoot SASS at close distances, be more historically correct and participate in NCOWs, hunt with them or simply collect them & hang them on the wall, that is fine with me.  Each to their own.  IMO, it just depends on what you, yourself want to do.

Billy 

[Coffinmaker]

  Yeso Bill   

I have obviously given the wrong impression.  I wasn't trying to be critical of your process nor your endeavor.  Nor was I trying to be disrespectful.  Or even cranky.

I was trying to be a mite humorous and show "my" endeavor which is actually to get minute of Pie Plate at 20 feet.  Oh, and be able to build up Dead Reliable Cap Guns. 

At no point did I intend to belittle.  If it came off that way, please allow me to apologize.  OOPS!!

[Yeso Bill]

No apology needed Coffinmaker.     I obviously misread your post.

Billy 

[treebeard]

Today was one of those rare nice days in south central Kansas with clear sky?s and 56f temps with almost no wind. So off to the range with my chronograph and several my cowboy guns. I had several loads for my 1873 SAA Old Model Uberti and 1873 Uberti Winchester? both 38-40?s. Found out it would be wise to back down a little from my usual rifle load if I Go to a CAS shoot- was a bit too close to the 1400fps limit at 1318fps. Glad I asked about that temp affect as it will be HOT in a couple months and a increase in velocity.
I will be testing black powder loads in the near future.

[Yeso Bill]

Today, and yesterday were nice days and I got some shootin' in.  Today was 70 degrees with a 7:00 3 mph wind.  Can't beat that.  (Humidity was on the usual 16)   

I've seen some warm winters but by far, this one is the warmest.  (and driest)  Some nights it isn't even freezing.  Unheard of. 

Springs a comin' but I dread several months of hard wind.  (Sometimes through May) 

I remember when I was a kid, the 1st of June would roll around and the wind would absolutely die....for the whole summer.  School would be out and I'd go out with Dad and help him rig up the gasoline powered pump jacks at the windmills.  Years later, electric lines were run to the windmills and water was then pumped with submersible pumps.  That's when the wind started blowing all year. 

Billy   

[Cholla Hill Tirador]

I have acquired a chronograph for testing velocity of my various reloads. I have never used one before and was curious on the effect of tempature on the velocities considering it is winter and here in south central Kansas i can only expect to have temps in the 40's and 50's for a while unless i get lucky and a good day shows up in the 60's. I reload for 25-20WCF Thru 44-40WCF, 45-70 and even 56-50 Spencer.

Velocity fluctuations where temperature is concerned is most prevalent with double-base powders. Most powders used in the type cartridges you mention are indeed double-base. I chronograph all my loads and have really never noticed a huge difference in velocities in straight/nearly straight wall cases like I have in modern bottleneck cases. Certainly not enough to worry about for shooting out to a couple hundred yards or so.

CHT

[Yeso Bill]

Treebeard & Cholla,
     When I shoot over the chronograph, I make sure my shells have been outside awhile and in the shade.  Winter or summer. 

The other day it was 70 degrees and I shot several groups sighting in a new 44-40 at 100 M.  The load was 21.6 gr. of H4198 under the Accurate 43-252 K bullet. 
The shells that were crimped averaged 1290 fps, SD: of 6.1 and ES of 15.0.  I didn't measure for group size but I thought they were a little big, indicating a little too much speed.  (I'd guess a 4" grp.) 

That surprised me and I thought they were 10 - 15 fps too fast.  But, I haven't been crimping my shells.  I ran out of light and quit.  It snowed and today it warmed up to 39 degrees and I shot the rest of those shells (6) this afternoon. 

Today's averaged 1229 fps. with an SD of 9.9 and ES of 23.1.  Grp. size was 6 in 2.7".  (still 100 M) 

So, this time a drop of 30 degrees cost 60 fps.  Since SDs were under 10, I believe that on both days, all shells had been loaded uniformly and went off the same.     

H4198 is advertised to be "extremely insensitive to hot / cold temperatures".  (https://reloadingunlimited.com/product/hodgdon-h4198/ )  It is a single base powder as is H4227.  RL 7, XMP 5744,  Unique, Herco and 2400 are double base. 

Dave Scovill's book, LOADING the PEACEMAKER lists a couple of loads using the single based Vihtavuori N320 & N330 using 240 grain bullets.  However, the Vihtavuori Reloading Book, (2nd edition, page 41) states 1% gain or loss in velocity per 10.9 degrees F.  (I think I converted that right from C )  So, rounding that off to 10,.... 1% of 1250 fps = 12.5 fps. per 10 degrees.  And that stuff is made in Finland where it is cold.  They suggest for winter hunting to either keep your shells warm or add powder.   (Imagine that  )

Anyway, I have not tried Vihtavuori  but from their literature, it doesn't look like there would be much, if any as those numbers are pretty close to my "general rule of thumb".  So, I have about decided that their is no magic gun-powder made for the 44-40. 

Billy

[Dirty Dick]

Lots of great info here, I just started using Trail Boss in my Uberti 73 .44-40, 5.5grs with Accurate 43-215 and I'm wondering if you had noticed an appreciable increase with temperature with it? This same load gave me a 1" group off the bench, cold, at 25 yards on our indoor range (I'm in Canuckistan, it's cold here) with my Pietta 7 1/2" SAA.

DD

[Yeso Bill]

DD,
     I have a can of it but I have never loaded enough of it to really test it out.  I'll put up the results when I do. 

Billy 

[Cholla Hill Tirador]

  Billy, look around here for some of the late John Kort's (w44wcf on this forum) load for the 44-40. He did an amazing amount of testing with this cartridge. His favorite powder was Re-7 because it filled the case and provided the highest velocities with the lowest pressures. He also posted a lot on the Cast Boolit forum. "Savvy Jack" can be found there and he too does tons of 44-40 testing.

Back to Re-7, I loaded some under a 220 gr. cast RNFP in my Uberti Sporting rifle and from its 24" barrel the numbers were: 23.0 grs.- 1254 fps, 23.5 grs.- 1338 fps and 24.0 grs. 1396 and 1404 fps (two strings of five). A search of www.loaddata.com generally shows 25.0 grs. as max, but I didn't see any need in loading that heavy.

  Regarding your 60 fps velocity loss, I wouldn't sweat it. The 44-40 is pretty much a short range cartridge and 60 fps is going to change the trajectory or how well it kills enough to matter. 

CHT

 

[Yeso Bill]

Hi Cholla,
     Yes, I first found Mr. Kort's files here and then corresponded quite a bit with him.  In fact, he is the one that fired me up on the 44-40 and recommended the 43- 215 C bullet.  After I put some sights on my rifles, I was soon knocking down the 300 M pigs with them using 3F BP.

"Savvy Jack" and I correspond quite frequently.   

My goal is 5 turkeys in a row and since the 44-40 is quite fickle in the wind, I've graduated to the 43 - 230 E, then the 43-245 C, then the 43-245 GC and now playing with the 43-252 K.  (a SWC weighing 259 with GC)  (The Uberti's I'm shooting have a 1:20 twist) 

I have shot lots of RL7 but my rifles are brass framers (60 & a 66) and I was always a little leery of going a full case full.  (I stretched a 38 spl. 66 back in the 1970s and don't want to do that again)  I settled on 21.5 gr. of RL7 under the 230 E and MV would usually be 1250, + or -.  SDs ran from 12 - 17.  No doubt the SDs would go lower if I added powder and if I had a 92 or a Marlin I would. 

Always a better mouse trap I say, so I switched to an iron frame Henry, heavier bullets and a slower powder - H4198.   That brought the SDs down to 10 and lower.  (Lowest has been 3.1) 

Now, today is almost dead calm.  I think I could probably go set up my turkeys, sight in my new rifle for 385 M. and knock over 5.  But then what would I do?

Billy

PS.  I do agree with you.  At "normal" 44-40 hunting range, 60 fps. isn't something to worry about.  Even at 200 M, it will get the chicky.

DD.  I found the Trailboss and some 215Cs.    Will try and load some up tonight.

Also, the 43-230E over a .030" Walters Veg. Wad and a casefull of OE III BP (34 +gr. ) is a real accurate load.  I torch it off with a Federal Match Large Pistol primer under a wax paper OP wad.  (in the case)  Depending on temps, that will run in the 1250s with low SDs. 

[Coffinmaker]

   Well gentlemen (use the term loosely), you're all missing the most important salient points.  The specific effect of temperature on velocity, on the Chrono, on standard deviation (I am Deviant) is absolutely MEANINGLESS!!!  Do you understand >> >> >> MEANINGLESS I tell you all   

Because it's currently just TOO DAMMN COLD TO GO OUTSIDE AND SHOOT!!  The most important consideration of the effects of temperature are on the SHOOTER.  I don't care if the cartridges are warm or cold or eve if you stick your cartridges to keep 'em warm .... or cool.  When I'm too COLD to go out and shoot none of that stuff matters AT ALL.  And .... pay attention here .... it's too damn COLD to shoot. 

[Bunk]

from central Texas I vote with Coffinmaker. My stay in temp is 60 degrees any thing below that is insane.

[Yeso Bill]

   Well Coffin Maker, I have plenty of room, come on down here to the SW and you will find it is too windy to shoot.

To top that off, I am the poorest offhand shooter there is in the whole country.  Bar none.  But to remedy that, (I'm 68), I lift weights and try and shoot the 1866 Uberti 22 every afternoon at the 22 silhouettes.  But it doesn't matter as I don't improve.  I weigh 125 lbs with hat, boots, spurs and 1 pistol and the wind blows me around worse than the 44-40 bullet.

Billy

PS.  After I finished the note above, I thought, "You are a durn fool if you don't go ahead and shoot",....because it was so nice until about 12:00 or so.  So I set the chrony up and the wind hit.  10-15 mph.  Better than yesterday as it was 35 - 40 mph.  Well, forget that idea so I went and fed the cows in the South Burro pasture.  Ran over a dead cactus, ruined a tire and since I had over a ton of feed on the pickup, decided it would be easier to simply walk the two miles in and use the front end loader tomorrow to jack up the pickup.  Almost sundown right now.  If the wind will lay just a mite more, maybe I can shoot the 22.

ADDENDUM - 2-8-20
Shells are loaded DD.  Pray for hot & cold weather.     

[Yeso Bill]

Lots of great info here, I just started using Trail Boss in my Uberti 73 .44-40, 5.5grs with Accurate 43-215 and I'm wondering if you had noticed an appreciable increase with temperature with it? This same load gave me a 1" group off the bench, cold, at 25 yards on our indoor range (I'm in Canuckistan, it's cold here) with my Pietta 7 1/2" SAA.

Howdy Dirty Dick!
     First let me say, that is great shooting.  Don't trade that Pietta.  I have one in stainless, 4 3/4", 45 and it is the best pistol I own.  I'd love to own one just like it in 44-40. 

First of all, I have shot very little Trail Boss and that was during a summer several years ago.  I pretty well started out with BP and the 43-215C bullet.  These were shot with a velocity of 1300+.  I graduated to heavier bullets and found that I could easily drive a 249 gr. bullet 1000 fps out of my 7.5" barreled 44-40 Ruger with BP.  (I say easy.  It was easy to load) 

As you are well aware, the Hodgdon site shows a starting load of 5.5 gr of TB under a 200 grain bullet with velocity out of a 6" barrel @ 723 fps.  Maximum load is 6.5 gr. with a velocity of 826 fps. and a pressure of 11.900 PSI.  So, I knew this powder wasn't going to work well with my heavier bullets and I simply haven't tried to use it. 

So, last week I loaded up 20 head using once fired Starline Brass and Winchester primers.  5.5 grains of TB under the 43-215C bullet.  (Alloy:  50 / 50 WW & lead.  They av. 220.5 grains)  Crimped with a Redding Profile Crimp die.  1.600" COL. 

On the 10th a Norther breezed in blowing some snow and I shot 10 of them at 34 degrees, 75 humidity.  It was overcast, poor light but the chrony worked.

All shot out of a 24" barreled 1860 Uberti.

Hi:  923.9 fps - # 3
Lo:  902.7 fps
SD:  8.1
Av:  914.2 fps
ES:  21.4 fps

Group was 10 in 2.5" @ 50 yards.

Today, (15th ) I shot the other ten at 68 degrees and our usual humidity of 16.  The days here are running in the 40s and early 50s (F) and I thought I had better not chance the "right now" vs a possible 3 degree warmer day tomorrow.   

Hi:  942.4 fps.  again # 3
Lo:  910.9 fps - # 4
SD:  10.4
Av. 928.9 fps. 
ES:  31.6

Group was 10 in 1.9" @ 50 yards. 
8 were touching measuring 1.5".    Good light today. 

Comments:
20 isn't much of a test.
There was an ES. Of 14 fps between the two groups and an ES of temperature of 34 degrees F. 
So, that is a loss or gain of 1 fps. per 2.428 degrees.  Quite a bit better than some of the 1 to 1 that it appears I have experienced with other powder. 

I wasn't real pleased with either group so I went and got some ammo that I have shot 3 - 4" groups with at 200 M.  The 6th shot made 2" at 50 yards and I said, "Well, it is only going to get worse; that's enough of that".   

Hope this helps.

Billy