Magnum revolvers, Lil Gun, & forcing cone erosion. But what about in a carbine?

GJgo · Jan 21, 2012

Hey all, I had a thought on a subject that I wanted to run up the flag pole. It's been documented, and I have seen personally in 2 of my revolvers (44 Mag & 460 Mag), that handloads using Lil' Gun powder lead to very fast forcing cone erosion & top strap cutting. I have since releived those guns from my stable, however I still have a stash of 44 handloads.

Premise backup- note the post by Bob Baker of Freedom Arms.

Subsequently I picked up a 77/44. (Love it BTW now that I shimmed the bolt.) I'm thinking that it may be OK for the carbine's throat to run these rounds through it and here's why, tell me if you disagree. I'm thinking that when used in the high pressure revolver cartridges, the fact that there's a cylinder gap leads to the presence of oxygen which causes the extra nitro content in this powder to burn excessively hot- just like adding O2 to the MAPP gas in a cutting torch. In the carbine's throat this is not the case, just as in the 410 shotgun bore that the powder is designed for.

Thoughts?

Side note, looking at the primers these handloads were at the top end in my 629, but in the 77/44 they look more conservative. Erosion aside & thinking of barrel length I'm wondering if Lil' Gun may be a better powder for the carbine than for the pistol in the big bore revolver cartridges..?

rcmodel · Jan 21, 2012

I doubt oxygen has anything to do with it.
Smokeless powder makes it's own oxygen when it burns.
And any free oxygen in the air at the B/C gap would be blown away from it with the first hint of gas escaping from the gap.

My feeling on gas cutting in revolvers has always been that unburned powder granules are blown out of the gap at supersonic speed and act as "sandblast" particles.

I have gas welded and used cutting torches enough to believe white hot gas from a revolver gap can't get steel hot enough to cut or melt it in the millisecond it is there each shot!

I actually have never used Lil' Gun in anything, so I have no opinion on how harshly it would treat a carbine barrel throat.

rc

Peter M. Eick · Jan 21, 2012

It burns hot because it is high in Nitroglycerin.

I tend to avoid it because when I was using it in my 10mm's it made the guns uncomfortably warm to hot. I think I finally burned it out and it will NOT be replaced on my bench.

RC has it right in my opinion also. Flame cutting is do to the unburned particles of powder exiting the cylinder gap and essentially sand blasting through the metal. It is the small particles of super hot powder doing the dead and not the flame per se. Otherwise how come say H110 will flame cut a 357max revolver yet 4227 will not?

GJgo · Jan 21, 2012

Thanks for the responses. Does anyone have an opinion if Lil Gun will cause any problems in a carbine's bore? Possibly premature throat erosion? 410s don't excatly have a "throat"..

ArchAngelCD · Jan 22, 2012

I like the results I get with Lil'Gun in a Carbine. It generated between 100 fps and 200 fps more than other powders I tested.

Clark · Jan 22, 2012

Didn't the 357 maximum get dropped because of flame cutting?

Isn't the most power one could get out of 454 Casull, 44 mag, etc. going to be with H110/W296 or LIL'GUN?

I am beginning to think that if they ran a non optimum powder in the 357 max, it would still be here.

Fleet · Jan 22, 2012

Didn't the 357 maximum get dropped because of flame cutting?

No, it got dropped because of no sales. Ruger quit producing the Blackhawk in that caliber because of flame cutting, but others continued for a time, notably Dan Wesson.

GJgo · Jan 22, 2012

ArchAngelCD, how many rounds of it do you have down the pipe? How does the throat look?

Grumulkin · Jan 22, 2012

GJgo said:
Thanks for the responses. Does anyone have an opinion if Lil Gun will cause any problems in a carbine's bore? Possibly premature throat erosion? 410s don't excatly have a "throat"..

If Lil' Gun will cause rapid forcing cone erosion in a revolver why in the world do you not think the same thing will happen to the throat of a rifle? It's never going through any of my guns unless I get a .410 shotgun and that's not likely to happen.

Sadly, before I heard of the erosion issue, I bought a pound of the stuff which sits lonely and unopened in my archives. Maybe someday I'll find some sucker who doesn't believe in the issue to take it off my hands but I couldn't sell it with good conscience without disclosure of my opinion on it.

GP100man · Jan 22, 2012

Flame cutting in revolvers will happen with any powder at the upper pressures , but some powders are still at a granular state at peak pressures & accelerate the process.

While we`re on the subject don`t forget `bout the Bluedot load behind the 125 gr bullets in 357 mag.

I use Lil`gun but in limited rounds of hunting ammo & even during testing with my revolvers I let the cyl/barrel cool inbetween shots !

The loads that Freedom Arms use in there revolvers are a little above SAAMI specs ,so I think it would be a perfect sceinario to see accelerated throat erosion using a hot burning powder !

To answer the OPs?? I think in a cabines chamber all the pressure & heat will be kept behind the bullet but erosion will still happen on the lands. but then again it will happen on all firearms, more so on the Hi Performance Hi Pressure rounds being developed in todays markets .

snuffy · Jan 22, 2012

Oldsters here will remember the now discontinued WW-630 powder. It's because it too would gas cut the forcing cones, cylinder gaps of revolvers. It didn't take long either! About 1000 rounds, replace barrel. :cuss:

How do I know? Back in the 70's I was heavily into the handgun silhouette game. My 7.5 inch 44 SBH was shot for 3 stages at each match. That meant a LOT of practice, a LOT of handloads with cast 240 grain bullets. I used WW-630 for all my shooting. I could rack up 2-300 rounds a month in practice and another couple hundred in a match. I got it by the 8 pound caddy! When I heard about the problems,(this was long before the internet), I took a look at my cylinder gap. EEK! It was huge, don't remember how big, but the back of the barrel looked like the end of a water pipe finished with a bastard cut file! :fire:

I still have some of the 630 left, I use it in closed breech single shots like the contender. I suspect that lil gun will work well in that 44 carbine.

buck460XVR · Jan 22, 2012

GJgo said:
Side note, looking at the primers these handloads were at the top end in my 629, but in the 77/44 they look more conservative.

Comparing primers from cases shot revolvers against primers from cases shot in rifles as a gauge of pressure is pretty much a waste of time and I doubt very much if any information at all could be obtained from the comparison.

My 77/44 likes H110/W296 and IMR4227 under a 240gr jacketed bullet. The 1/2 lb of Lil' Gun I had left after trying it for a while in my revolvers(before the evidence of premature erosion) fed my wife's flowers. The little value it had left(what 9-10 bucks?) wasn't worth the risk of using it in the Ruger or my handgun caliber levers.

GJgo · Jan 22, 2012

Well, I'm not going to pull all my Lil Gun rounds so perhaps I'll stash them for just in case. I'll switch over to W296 for the carbine & call it square.. Thanks for the opinions.

ArchAngelCD · Jan 24, 2012

GJgo said:
ArchAngelCD, how many rounds of it do you have down the pipe? How does the throat look?

I don't have any special tools for checking but by eye it looks like there are no ill effects. I doubt I've fired more than 500 rounds made with Lil'Gun through my 1894C. (maybe as little as 400 rounds)

454PB · Jan 24, 2012

Too bad hazmat shipping is required, because I'd take all that Lil'Gun off your hands if you don't like it.

I've been using it in my .454 Casulls and .44 magnums with no more erosion than I got from H-110 or 296.

Anytime you shoot revolver loads at 40K to 60K pressure, you're going to get some forcing cone and topstrap erosion.

Magnum revolvers, Lil Gun, & forcing cone erosion. But what about in a carbine?

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