Twist rate for 38-55 & 335gr CB

[Range Gypsy]

I am reworking a shot out winchester highwall that was chambered in 32-40 to create a 38-55. I want to use a 335 gr bullet and want input on what the best twist rate would be.

[Bullshop]

I would go 1/12" same as used for the 375 H&H and the 375 Win.
Certainly not slower than 1/14". I have a 1/14" and it will only stabilize the 330 Lyman to about 300 yards. After that they begin to buzz. It does well with a 320gn from NEI out to 800 yards but the NEI design is somewhat shorter.
I regularly shoot a 350gn LBT LFN from the 375 Win with 1/12" twist. It does very well at mid range but I have not tried the 375 Win from my Marlin at long range.
I would prefer my 38/55 roller with the 1/14" to be a 1/12"
BIC/BS

[montana_charlie]

Dan Theodore recommends a 1.425" bullet in a 38-55 with a 1 in 12 twist barrel.
How long is your 335 grainer?

CM

[Boz330]

I have a 38-55 with a 15 twist barrel and it does alright out to 600yd with the Lyman 335gr boolit. I have 2 friends that are using a 14 twist in a 38-50 Hepburn out to 600yrd as well. The 12 twist would probably lend itself to the 38-70s and 90s with 350gr+ boolits.
If you are going to shoot smokeless that might be a different matter, but you posted in the BP forum.

Bob

[John Boy]

Guess I'm old fashioned - 1:18 and a 320gr bullet, preferably the Ideal 375166 that was in the Ideal Handbooks for many decades:
First Range Test 38-55 Ideal 375166 (http://shilohrifle.com/forums/viewtopic.php?t=13911)

[Bullshop]

John boy
Looking at your targets I do believe I see evidence of tipping. Look closely and you can see to the side of each hole there is a rub mark. This for sure shows there is some wobble going on there. A wobbling boolit is an unstable boolit. I too was getting good accuracy to 300 yards with my 1/14" twist and a Lyman 330 BPC. When I went to longer range accuracy went to pot, couldn't even hit the pallet at 500 yards.
I could actually hear the boolits begin to buzz about half way to the 500 yard target.
The slight tipping at close range continues to get worse until they completely tumble.
I hope you don't take this as offensive because I mean only to help myself and anyone else to know for sure what works. To me your targets clearly tell the story of a not completely stabilized boolit. It may have done well at 100 and 200 but if you keep moving the target a bit further out I think you will get the same results I got.
If you have access to a 500 yard range give it a try.
I think the idea you put across is that what I said about a faster twist being needed for heavy 330gn type boolits is really not true because you have proven that you got good accuracy at close range. You really have not proven or dis-proven what I said about the twist needed for long range with heavy boolits in the 38 bore.
I think as I said that if you do enough testing you will find that I am right. If I am right then you may be misleading to others that are looking at what is needed just as the fellow that started this thread.
No offence intended just trying to get to the facts so we can eliminate the error part of trial and error.
BIC/BS

[felix]

In a nut shell, it all about the amount of time to the target. If given the choice, I will use the very slowest twist to get the job done given the most common conditions I shoot in. Only hungry hunters need to worry about that long shot in sorry conditions. ... felix

[Bullshop]

I agree Felix, the slowest twist to get the job done. He has asked specifically about the very long Lyman 330gn boolit in a 38 bore. I have been very specific about my experience with exactly that.
It has nothing to do with hungry hunters it has everything to do with answering his question. Did you look at the targets posted by JohnBoy? The boolits are obviously not spinning true. Are you saying that that is acceptable to you for accurate shooting?
Knowing your history of BR shooting I think not. I know that you know what that wobble means, increased drag and lowered BC. The wobble will increase the TOF and lag time and even at close range to 300 yards will exaggerate the effects of the conditions. I think anyone interested in achieving best accuracy will do their best to combat those things not to increase them or accept them.
Am I wrong Felix? Somehow what you are saying here seems contrary to what I would have expected from you knowing of your involvement with accuracy shooting.
I seriously doubt anyone in the game will settle for a twist rate bullet/boolit length combo that is obviously lacking in rotational velocity to keep the projectile spinning on its center axis.
I am confused with your answer. Please explain.
BIC/BS

[felix]

No, you are definitely not wrong, Dan. The ideal twist would be 15 to clean up the egg shaped holes using his boolit of choice. Reasoning is that 16 twist will do 235 grainers in 358-360 just about perfectly, and we know that 18 twist will do the same with 250 grainers at 18 twist in his gun at 375-380. His (JB's) target does show some wobble as you say with his boolits and barrel as they are now, but accuracy is acceptable under the conditions stated. Therefore increasing the twist slightly will correct the imbalance and accuracy should increase. However, for hunting live critters with heavy weight projectiles I would like an imbalance to set in when the target is hit. This would compensate for a non-expanding boolit having like expansion at the tail of the boolit in emulation of the expanding forefront. This logic comes from the extra killing power induced by the 16 twist in the 323 guns when compared to the 308 guns having 12 twist, assuming closer game ranges, of course. ... felix

[Bullshop]

OK so we are on the same page then. A little wobble may be OK to enhance killing effect true but if we are looking for the utmost in accuracy any wobble is unacceptable.
As you first stated just enough spin to get the job done but if there is any wobble its not enough twist for that boolit at that velocity.
JB must have been pleased with the grouping he got from an unstable boolit but how much more so may he realise success under all conditions if he would accept the truth of the matter.
I see it often the "you guys are wrong because look what I did". Yes true decent groups can be fired with boolits/bullets that are not quite stable usually under ideal conditions at moderate range. Change the conditions as in add a brisk variable wind and or add range and the problem becomes more apparent.
Even if you have a very precise BC calculation for the boolit and velocity all bets are off in trying to compute drop or drift if there is any wobble.
I am not trying to put down anyone or their ability just want them to understand if they get decent results with something that's not quite right think of how well it could be when all is exactly correct.
Hope I have not offended anyone by being rather contrary to the flow here.
BIC/BS

[Range Gypsy]

Thanks guys, it's been informative. I guess I didn't specifiy the purpose for the gun. It will be for BPC target shooting, using a lead boolit and BP. At present in our area we are only shooting to 250yrds as that is the limitation of the local ranges. But intrest is growing and we are trying to gear up to shoot farther and I want to be able to keep up with the 40-65's and 45-70's etc.

Thanks again
~ Range Gypsy

[John Boy]

John boy
Looking at your targets I do believe I see evidence of tipping. Look closely and you can see to the side of each hole there is a rub mark. This for sure shows there is some wobble going on there.
BS, nope, the holes showed no signs of tipping. I thought the same when I was looking at the holes with the scope. At the paper (pressing the target in from the back) the holes were perfectly round. As for the rub marks, maybe the 6 GG's on the bullets have something to do with it. Also, I was using a cardboard backer which will cave in when hit. Might add, I was using NASA Lube too!

As for stability, with a velocity of 1105 to 1180 fps, the bullet calculates exactly to a 1:18 twist with a Stability Factor of 3.20 -3.25 which is > 1.5 SF for maximum stability. And using a black powder formulation of the Greenhill that was in the 2007 issue of the Black Powder Cartridge News, the Ideal 375166 has a 17.65 ratio for a 1:18 barrel. And I have shot it at 600yds with no indication of tipping or key holing

Can't say much more other than it is one darn good shooting bullet. The best of the 3 other 38-55's I've cast and shot.

[John Boy]

Bullshop, you made me curious about the holes on the 375166 target at 600yds. To be sure, dug it out of the pile - all holes were perfect hits and all had the gray around the hole.
So, it's gotta be your NASA lube! [smilie=1:

[Bullshop]

John boy
Not the lube, your gun is magic. Wanna sell it? Keep up the good shooting.
BTW thanks for the plug on NASA lube.
Blessings
BIC/BS

[John Boy]

Bullshop, isn't the rifle, it's the bullet.
I picked up an original Ideal 375166 mold that had the base widened and enlarged to 380. I thought I was in heaven finding the mold. Loaded up some, shot them at 200 and 300 yds. They didn't group half as good as the 375166 with the original dimensions

It's the bullet that is magic, not the rifle. The mold can still be had
Ordering Instructions:
Order By Mail, Check or Money Order …
Price of the Mold - $75
Shipping - $10.00 plus $1.70 Insurance ($11.70)
Price of Top Punch - $8.50 (Optional)
Price of the Sizing Die - $19.95 (Optional
Send a letter with your shipping information and a check or money for your total purchase to:
Lou Sellman
2003 Ewings Mill Rd
Corapolis, PA 15108-3311

Order By Credit Card
Call Lou at (412) 299-0412

Lou Sellman email address … reloadersequipmentonline.com or customcastbullets@yahoo.com

[Bullshop]

I am begining to realise that I may be confused. (stop laughing)
Is this not the standard Lyman offering we have been talking about? The Lyman 330gn Postell type design? Sorry I dont know the mold number.
If no I sure would like to see a pic of the one you have been talking about.

[Boz330]

The reduced Postell is 674, the 166 is a Lovergn design. The 674 shoots just fine out of my 38-55 out to 600yd with a 15 twist.

Bob