.38 Special seating depth? Bullet jump?

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Last Post 04 July 2016

CBA Member

harleyrock posted this 25 June 2016

Does a revolver bullet need to jump from the cartridge mouth to the cylinder throat? Or would it be more accurate if the bullet was touching the cylinder throat?Things to consider: The longer seated bullet would increase free space in cartridge, affecting pressure lower. Bullet touching throat would start with more resistance, affecting pressure higher. Bullet would be centered in throat by contact that should affect accuracy in a good way. The particulars:Bullet: Lyman 358477 154grains outdoor range scrap air cooled BHN ~ 9 (pencil test) Sized .358. Case: unfired Starline 1.14” CL. Powder: 5.4gr Hercules Unique. COAL: Seated to crimping groove=1.47” Seated with front driving band touching cylinder throat=1.51". Revolver: S&W Model 14-3 K-38 Target Master Piece. Cylinder throat= .3575. This load appears to be a +P load. This bullet and load is Glynn Fryxell"s favorite .38 Special load from his book” From Ingot to Target: A Cast Bullet guide for Handgunners". He doesn't mention seating depth. So, which would be better, seated to crimp groove with bullet jump, or seated with bullet centered in the cylinder throat by contact? <I tried to make this more readable with proper spacing and paragraphs, but I don't know how to make a paragraph break>

Lifetime NRA since 1956, NRA Benefactor, USN Member, CBA Member

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Dale53 posted this 25 June 2016

harleyrock; I could give some theory but the real test will come from actually shooting from a rest.

My personal preference would be to seat and a good crimp in the crimp groove. Test the load (I find it convenient to test at 25 yards) and if the load shoots under an inch at 25 yards, then I am “good to go". You can then test at whatever range you need to.

There are conflicting factors at play. You will probably get a better burn from Unique if you utilize the crimp groove.

My general range load (and field use) is often a “full charge wadcutter” as recommended by Ed Harris. However, I have often used a good SWC in the .38 Special for both field and range use. The SWC will generally give better results past 50 yards as, generally speaking, the full wadcutter becomes unstable somewhat past fifty yards. I have done much shooting at 100 yards with handguns and a good load can be accurate much farther.

FWIW Dale53

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RicinYakima posted this 25 June 2016

I agree with Dale53, except that I seat my full WC's only half way into the case and use the other half in the throat for guidance. I would let the holes in the paper tell you what your revolver likes, and spend less time on the suppositions from the inter-net. I am currently using SR7625 as I have several pounds, and prior to that WW231. My loads are about 800 f/s, and it does everything I want from a 38 Special. FWIW, Ric

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Ed Harris posted this 28 June 2016

Ideally you want the front end of the wadcutter to begin to engrave in the rifling before the base of the bullet clears the cylinder. Factory HBWC bullets do that. Shorter DEWCs may not, depending upon cylinder length and forcing cone angle. The Colt style 11 degree forcing cone is generally better than the older S&W style 18 degree cone. You will see alot of Rugers cut with very gradual 6 degree forcing cones, which work well IF they are smooth and concentric.

One thing we found out at Ruger was that is the shoulder angle which transitioned from the .380 diameter at the case mouth of a .357 Mag. or .38 chamber, to the .358 diameter cylinder throat, was reduced from the usual 15 degrees to 6 degrees, that accuracy with lead bullets improved. A .357 chamber so cut would shoot very well with .38 wadcutters and +P service loads. A .38 Special chamber so cut also improved.

Jim Clark, Bob Collins and Bill Davis all recut their PPC revolvers this way. This was one of the “secret” wrinkles used to produce ragged hole 50-yard groupers...

Tried to get Ruger to make the GP100 this way, and some earlier ones were, but eventually SAAMI Specs and lawyers changed everything back after I left, when the reamers wore out...

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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harleyrock posted this 03 July 2016

Thanks, Dale, Ric and Ed. Do you have any suggestions as to where I could get my cylinder and forcing cone so modified?

Lifetime NRA since 1956, NRA Benefactor, USN Member, CBA Member

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RicinYakima posted this 04 July 2016

When I was shooting International “Duel” with a Colt 357, there was a company called “cylinder and slide", but that was many years ago. You might find someone how still does PPC work.