.38-55 head scratcher

[flatnose]

.002 over groove dia. 4759 if you are lucky to have some if not 5744. Data for 5744 on Hodgon website. You wont regret this.

[Abert Rim]

Fellas thanks. The rifle was barreled with a Douglas .375 groove barrel and can be loaded as a .38-55 or a .375 Winchester. It was custom built by a retired Army armorer and gunsmith in Iowa for a gentlemen who wanted a very accurate rifle for lever gun competition. He then developed Parkinson's and had to sell all his guns.
This is the rifle I am working with. Repeat: This barrel is .366 on the lands and .375 in the grooves -- not a .378, not a .380, not a .382. I know about the larger .38-55 groove diameters. I actually went into commercial swaging some years ago after reading a Ken Waters piece on bullets he'd love to see available again for the "old ones" to produce a .379 softpoint specifically for the older rifles and the Marlin Cowboy. Ken was so tickled when I sent him a box, explaining that he was the inspiration for me spending a lot of money with Dave Corbin that he wrote up my "Boer Bullet Co." bullets in Handloader -- and sent me a Christmas card.
So I return to scratching my head as to why a bullet sized .376 and fired in a squeaky clean barrel with a .375 groove should keyhole wildly. Only two of the five rounds I fired struck the target paper -- sideways of course, and the rest struck the frame. I have some loads put up with 5744, but will assemble some over 9 grains of Trail Boss (per the Lyman 51st edition) to see if slowing things way down might help.

[Abert Rim]

Delkal, I agree. I think a moderator has to do it. I don't know how.

[Mk42gunner]

A 1:14" twist should be more than sufficient for anything you can load through the action. Your dimensions sound good to me, and you say the crown is good.

What about the throat? Maybe do a chamber cast. Although I don't see how a large or "bad" throat could cause keyholing.

If all else fails, try a larger boolit, not terribly large, just a few thousandths larger like .377 or .378".

Good luck,

Robert

[G W Wade]

I am shooting something similar , an RCBS 255 over 16 gr 2400 for 1300 fps ( factory duplicate 38/55) and everything is great. Have not checked my book but 23.5 sounds extreme. Good Luck GW

[rockrat]

Might be pushing them a bit too fast for a non-gas checked boolit. Try powder coating a few and size to about .377" and try and as an alternative, drop the charge back to about 18 gr. or so with the boolit you are casting, non powder coated.

[indian joe]

2400 needs some pressure to burn completely. While your load sounds like plenty of powder (I didn't check) if you were getting variable ignition the sideways load could be from a case that didn't ignite completely and had too low of a velocity to stabilize. Like others have questioned was the rest of the groups OK? Did you notice a lot of unburnt powder or a difference in recoil?

I would try another powder. Maybe a pistol powder for light loads or an IMR powder for standard velocity. And if you have a chrony use it and check the velocity and ES.

I dont know 2400 but my old Lyman book says 16 to 19 grains under a 255 grain cast ---is 23.5 a bit stiff ?
I proly go with the others that say boolit fit - first thing to try is unsized -

[Delkal]

I still think this is due to velocity. Shooting a bullet a few thousandths under bore diameter does not make a bullet keyhole like that at 50 yards. If the velocity is too low the bullet will not stabilize and if it is too high it could strip the rifling and tumble. Was the barrel heavily leaded after a few shots? Do you have a chrony?

[akajun]

ill add also slug both ends of the barrel, make sure that the muzzle is smaller than the breach, at least the same size.

[Delkal]

Just looked in Lyman 41st edition and for a 38-55 with a 250 grain plain base (375248) the max of 2400 was 18.7 grains and suggested was 15.0 grains. They also had a suggested load of 10.6 grains unique (no max). The suggested loads were from 1200-1300 fps.

[JFE]

My guess is you’re pushing a PB bullet too fast. Out of a 28” barrel 23.5gr of 2400 behind that pill is probably doing close to 2000fps. Way too fast for a PB bullet. You didn’t mention whether your load leaded your barrel.

Try a lower velocity load, something generating less than 1400fps.

[Pereira]

I dont know 2400 but my old Lyman book says 16 to 19 grains under a 255 grain cast ---is 23.5 a bit stiff ?
I proly go with the others that say boolit fit - first thing to try is unsized -

I agree as to the fact that 23.5 is a bit much.
I have a Marlin Cowboy with the 24" tube and 15.0 grs. of 2400 with either a 250 or 255 gr pill is quite accurate.
10.0 grs of Unique over a 240-245 pill works well also, haven't tried it yet but bet a 250 grainer would work as well.
The guy I bought it from used it for long range dinger ringing, and his favorite for that was 21.0 grs of IMR 4198 and a 260 gr pill.
I've used that load with some 255 gr. that was pretty good.

RP

[koger]

I would try between 20-24 grain of IMR 4198, what my 38/55s all love.

[koger]

The lee bullet drops at 265 grs with my alloy of half wheel weights/soft lead, plain base, PC or lube it shoots great out to 600 yds as far as I have shot it.

[Delkal]

My guess is you’re pushing a PB bullet too fast. Out of a 28” barrel 23.5gr of 2400 behind that pill is probably doing close to 2000fps. Way too fast for a PB bullet. You didn’t mention whether your load leaded your barrel.

Try a lower velocity load, something generating less than 1400fps.

And don't forget the OP cast the bullets out of range scrap that is ~BHN=10 if he is lucky.

Pushing a soft plain based bullet to ~2000 fps? Seems like this isn't really a head scratcher.

[Abert Rim]

Lyman 51st shows 1700-1800 but yes, that's probably much too fast for range scrap. I have some loaded way down around 1300 and will see how they do. Taking a closer look, I do see some leading. Probably put way too much faith in Lee Liquid Alox.

[gc45]

Your bore and groove sounds fine. Definately an overload. Dump the 2400 and like another said try 5744 using published powder charges only, Use cast boolits that are semi soft, BN10 works great for this, make them .001 to .002 over groove dia. 15,000 rds and still going, it just works. .375 is smaller than origional 38-55 rifles, many needing .380 Boolits to shoot well. IMO- your barrel is more the modern size and suited for jacketed bullets in modern steels and why cast is great because, we make them to a proper size that with good lube seals up with shooting them.

[indian joe]

have a 94 winchester comemorative (Oliver F Winchester) in 38/55 - shoots that LEE 250 grain boolit straight from the mold over blackpowder - that combo is seriously accurate

[Abert Rim]

Joe, I will load some with Olde Eynesford, just because it is the right thing to do.
The more I think about these issues and this thread the more embarrassed I am that it did not occur to me the velocities expected were too much to ask of the Lee bullet with Alox only. I powdered coated some this morning and will try those at around 1600 or so and bet they will be fine.
I am using published data, but I think a second issue is for me to quit thinking of this as a .375 Winchester and focus on it as a .38-55 with tight bore and relatively fast twist. I have reached the age where it is easier to get confused, sorry to confess!
Bill

[Abert Rim]

Made up a sample of five rounds of the Lee bullet, powder coated and hand-lubed with SPG over 40 grains Olde Eynsford FFg drop-tubed, wad seated and compressed by bullet seating. These ought to be fun.