Bullet to Bore diameter

[J.D. Yellowhammer]

Howdy,

I've been doing a lot of BPCR shooting lately and I just got another rifle, a 38-55.  I haven't slugged the barrel, yet, because the rifle is sitting in the shop thanks to the "instant check" computer, which wasn't (it still galls me to have to go through all that for a long arm, but that's not why I'm postin').  But I'll slug it as soon as my rifle is released from federal purgatory.

Anyway, the literature says the bore diameter is .376.  I happen to have boxes of 20:1 lubed .377's, .378's and .380's from a previous 38-55 which I sold.  I usually use bullets that are .001 above bore diameter, which means the .377's if my bore is on spec.  I usually use Swiss powder, by the way.

Given considerations like pressure, leading, accuracy, etc., what size bullets do you use in relation to your bore?

Thanks,
JD

[Dick Dastardly]

According to the Lyman gospel, a thousandth or two over bore is best with a 1:20 bullet.  I find that some guns will run with undersize bullets, but not many.  Most like the Lyman plan.  My own rifles do best with mild cast bullets lube sized to bore size.  Each rifle and load will have a preference.  Load 'em, shoot 'em and take notes.  A graph helps.

DD-DLoS

[J.D. Yellowhammer]

Thanks, DD.  I'll follow your advice (and my rifle's).

With my old H&R 38-55, I was keyholing the targets until I used bullets at least 1/1000th over.  I can't wait to try the new one.

[Dakota Widowmaker]

DD has the right idea.

1-2 thou is where most shooter will find best accuracy and then adjust powder levels and bullet profile as needed.

Now if you are going with smokeless, then its a whole nother game. You need to adjust for pressure, velocity, and barrel twist more so than with BP.

I find my rebarreled Winchester 94 works best with a 245-265 gr medium cast (not too soft, not too hard - about 13BHN) bullet with a rather long nose and a flat plain base. I had a custom mold made from Mountain Molds to get one that would work with W-W brass, which is only 2.06" long. I needed a driving band that was .05" farther forward than "classic" 375/38-55 designs today.

I also wanted one that dropped right at .3775", so, I ordered it at .378" and use a light coating of graphite spray.

Starline now has propper length brass for 38-55 chambers and you can go back to using traditional bullet designs.

You are going to want an OAL of 2.54" if you work a lever gun (your an H&R, so this is not an issue)

I believe the H&R guns use a .378-.379" bullet in the 250-300 grain range for best results. Shooters are talking how nice the new Starline brass is working for them. (moves the driving band a full .05" farther forward which REALLY helps accuracy)

GOEX Express FFg is what I use and have a nice tall drop tube to get a full 50gr inside the cases.

[J.D. Yellowhammer]

Thanks, DW, fer the detailed info.  That's interesting about case lengths.  I just had a box of commercial cartridges that didn't want to chamber--they were too long.  I should have put the caliper to them but they're all gone, now.  I went to the range yesterday and shot some loads I worked up using .377 bullets, 250g, 20:1 SPG lubed, from Buffalo Arms.  They shot great on top of some Swiss 3F that I have.  I need to order some 2F, but I've got several pounds of 3F now so that's what I've been loading.  By the way, I don't have the H&R anymore--I just got a Winchester 1885 hiwall.  I think it's the most accurate rifle I've ever had.

I have a box of .378 Postels I'm gonna try next.  Man, I love playin' with this stuff!  I cannot fathom why anyone would have wanted to create smokeless powders.

[Steel Horse Bailey]

Howdy!

I can't add much, but I have heard about the 2 basic differences in case lengths - mostly between old guns and new.  Does anyone know why?  Most of us have heard about the various measurements involved with the 44 WCFs (44-40) and why, but what'd be the purpose in making shorter or longer chambers/shells?  (I BELIEVE that the longer length, like Dakota W mentions - made by Starline - are made to the old, original specs, and the shorter ones are newer.  )  Any ideas?  I've got no dog in this fight - my big gun is 45-70; but I AM curious.  I've also heard that the 38-55s are one of the absolute sweetest shooting, med. range calibers that you can shoot!

[J.D. Yellowhammer]

(I BELIEVE that the longer length, like Dakota W mentions - made by Starline - are made to the old, original specs, and the shorter ones are newer.  )  Any ideas?  I've got no dog in this fight - my big gun is 45-70; but I AM curious.  I've also heard that the 38-55s are one of the absolute sweetest shooting, med. range calibers that you can shoot!

I'll have to get out the calipers and start measuring my shells, I'm real curious, now.  I've been using new WW's and whatever shells I have from shooting commercial rounds.  Maybe some of them are Starlines.  I should measure my chamber, too.  I can't figure out why shell length would be different, especially in a cartridge that's been around so long.

Mr. Bailey, I can tell you for sure that shootin' a 38-55 is a pleasure.  It has plenty of power to shoot on the relatively short "long ranges" we have here in the east.  I was shootin' today at 200 yards and the rifle wasn't stretching at all.  It's a mighty accurate round.  And the recoil is nuthin', specially after shooting my 45-70.  If you can ever get yer hands on a 38-55, I highly recommend doing so.

[Steel Horse Bailey]

JD, I've got a pal who is itchin' to load for his 38-55 and when he does, I'll be in on it.  And the shooting. 

I'm lookin' forward to it. 

[Delmonico]

The 38-55 is the base case for the later 30-30, but the 30-30 is slightly shorter.  The later production 38-55 from what I understand is just 30-30 with out the bottle-neck and comes out shorter, the same as the heavier cased 375 Winchester.  Saves on setting up for small prodution runs.  Just depends on which cup they use as to if it comes out as a 38-55 or 375, the 375 being heavier in the head for the higher pressures.  Then if it is to be a 30-30 they run it through another die.  Then one just needs the proper stamp in place to headstamp the caliber.

[Springfield Slim]

The trouble with some 38-55's is that the chamber is a little small for the bore, especialy the H&R guns. I can shoot a .380 Big Lube(tm)  bullet but only if I load very carefully and don't over-do the crimp.

[J.D. Yellowhammer]

I used to have an H&R 38-55.  The bore was .379 or .380, can't recall which.  When I first got it I tried shooting .377's and they tumbled and keyholed the target. Then I slugged the barrel and found the problem.  It did fine with .380's.  This new Winchester 1885 is the opposite--tight bore.

I have a box of 50 .380's from Buffalo Arms.  They're 275g, 20:1, SPG lubed.  I'd trade even for a box of .377's.     

[john boy]

... for what it's worth:  Three thousands over bore will obturate better, especially with a 1:20 or 1:30.
If your 38-55 is the H&R Target rifle, because of the 0.002 groove diameter over bore ... it likes a hard bullet in the WW + 1% tin range with 380 bases.

For the Hi-Walls, I'm shooting 380's too with good accuracy out of a Uberti

[J.D. Yellowhammer]

That's good to hear, John Boy.  My 38-55 is a Winchester high wall.  I wasn't going to use the .380's because they were so much bigger than the bore, but I'm gonna try them out, now.

I take it that you're the same John Boy as on the other forums.  I thank you--you've helped me a lot as I start seriously working on BPCR.