Discussion in 'Handloading and Reloading' started by Mr_Flintstone, Nov 28, 2021.
In a proper functioning carbine, and with ammo that's within spec, there should be no danger of slamfire.
A subscriber wrote in with a VERY similar question about 30 Carbine.
Is that you?
He said he couldn't find any small rifle primers and was questioning what primers to use.
Writer Brian Pearce said 2nd choice would be small pistol magnum.
He said with SPMs use of Accurate #9 or Alliant 2400 would be good choices
He also said even ammo mfgs are unable to source small rifle primers.
Hope this helps.
No, that wasn’t me. I’m glad someone else asked the question though. I’ve been burning through my SRPs with .223, and was just wondering if the SPMs would be an alternative if I couldn’t find any in the coming days.
The .30 carbine has a fairly light firing pin and the bolt doesn't move as far as they do on other military self loaders, so I think the more sensitive primers are an acceptable risk.
I shoot regular CCI small pistol primers in my .357 SIG and some of those loads are running close to CIP max pressure of 44,000+ psi.
I haven't tried it, but I'd feel pretty safe using CCI 550's in my .30 carbine cast bullet loads. I don't have my load notes with me, but my usual load is a little under 10 grains of 2400 with a 120 grain powder coated cast roundnose.
I don't know what the pressure is and I've never even chronographed the load, but the brass usually lands within two feet of my right boot, so definitely not high pressure.
I recommend using the least sensitive primers in these Garand type mechanisms. These devices do not have a firing pin block, the firing pin is free to rebound off the primer for most of the bolt travel. Pistol primers are more sensitive than rifle, and I recommend CCI #41’s, which are the mil spec rifle primer, which are less sensitive than the commercial rifle primer. Going more sensitive just increases the chance of an in battery or out of battery slamfirfe.
I used to collect slamfire reports on the M1 carbine, a couple are so old the links are busted. Compared to Garands, M1a’s, and now AR15’s, there are not a lot of M1 carbines being shot. The M1 carbine is so inaccurate, and the cartridge was never a long range round, that the M1 carbine was never used as an across the course rifle. Some clubs have M1 carbine matches at 100 or 200 yards, but these are the occasional fun match.
I collected more slamfire reports on Garands, M1a’s, simply because there were more people shooting the things, and thus, more slamfire reports. And then the AR15 became massive, and there are a surprising number of AR15 slamfire incidents reported on the web.
Out of battery Slamfire in M1 Carbine with Federal American Eagle Ammunition.
Witnessed 'powder burn' at the range today
Anything is possible I recon.
IF I ever find and buy a M1 Carbine, I will have to remember and see if pistol, magnum, or rifle powders make a difference.
Yup! Seen it happen! I only use #34's or some form of LRMP in Garands. #41 or SRMP in carbines. It's not just the possibility of a slamfire - but that's a real thing and you don't want to be holding one when it happens - it's the possibility of a pierced primer, too. Those thicker cups and angled anvils serve a purpose. BTW: I also use them for the .35Rem ammo that goes through my Remington Model 81. I've had Remington factory ammo push gas through that big ol' action block and it ain't nice! Those parts are hard to find and $$$$$!! when you do find them.
All I've ever used in 30 carbine is CCI 450, because H110 and 4227 tend to light off better with a magnum primer.
I should also mention I shoot as many of my reloads with my Blackhawk as I do with my M1 Carbine. Probably more!
Something worth considering is installing a new "Hammer Spring" from Wolff. https://www.gunsprings.com/M1 CARBINE/US M1 CARBINE /cID2/mID98/dID163
The hammer spring in an original M1 carbine has to be 50 to 75 years old. A lot of carbines were rebuilt in the 1950's, and I assume, early 60's, and the hammer spring has been in compression since them.
This is a picture of a 1968 ish recoil spring to a S&W M46 target pistol. It had been hardly shot, it was just in compression since new. Look how much of a set it had taken before I replaced it with a new recoil spring.
If your Carbine still misfires with a new hammer spring, I would then recommend commercial rifle primers, which are more sensitive than the military spec. I am leery of Federals for gas guns, as they are the most slamfiring primers in Garands and M1a's. Federals are outstanding bolt gun primers, and pistol primers, but for a mechanism that has a free floating firing pin, rebounding off the primer, before bolt lock, I want something less sensitive. A CCI standard small rifle would be my next choice. Federals are too sensitive, and Winchester increased the sensitivity of their WSR primer in 1999.
this is a military M1 carbine
the upper firing pins are for a Garand, M14, and the bottom is the Carbine. It was not milled to lighten the thing, and having never weighed the thing, I don't know if it is heavier or not.
As for Brian Pearce's recommendation to use pistol primers, I think that is nuts. He did not conduct an analysis on the sensitivity of the military primer and that of pistol primers. And he should have asked his puppet masters in the gun industry for "their analysis". Which I assume, they have not done either, as why should they? They, like their gunwriter sock puppets, don't really have any liability for the accidents that occur with reloaded ammunition.
Sammy, our last WW2 veteran, ran matches and participated in high power matches for years. When it came to selling off the Club's Garands, which were bought from the CMP in the 1960's, Sammy was the property book Officer for the club, and it was over to Sammy to pick up a rifle. One I handled, was in very good condition and was almost all matching except for the bolt. Sammy told me that was the rifle he earned a Master's card (in the early 1960's). And, the reason the bolt did not match was because the original bolt came out of the rifle during a 300 yard rapid fire event. The Armorer on the line decided the ejected bolt was defective and put in a new bolt instead, and Sammy continued shooting. The rifle was not damaged in any way and Sammy was concentrating on sight alignment and trigger pull, so he had no idea why his rifle kicked out its bolt on the firing line. And I was also pretty baffled by the concept.
But later I remembered a post I read about a Marine shooter's M14 ejecting its bolt into the forehead of the shooter, at Camp Perry, during prone rapid fire. The poster claimed all the NM ammunition was withdrawn from the line and a new lot issued. The Marine shooter was not hurt badly enough to not continue shooting, and the whole National Match continued on.
I also read a post by @Hummer70 in which he states American dead in Korea were found with carbine bolts in their foreheads.
Just this year, I re verified an account with a USMC shooter. He was a USMC Rifle team shooter in 1972, and he showed me a picture of his team, at Camp Perry, just after his team won the 1000 yard match, with M14's. The M14's and the Campaign hats were very predominate in the picture. (P.S. the military teams create several sub teams from their members, so you will see a USMC Gold and USMC Silver or USMC Red and USMC blue on the firing line during team events.
Anyway bud told me of two incidents he personally witnessed where M14's puked their bolts out into USMC rifle team shooter's eyeballs. He said the rifles were damaged, and that one shooter lost his vision in his shooting eye, and the other shooter was severely hurt, had to be hospitalized, but evidentially kept his eyeball. These were military rifles, built by Marine Armorer's, using military National Match ammunition. Bud had no idea why these events happened, and I am going to tell you, the military does not spend any time teaching their people about rare failure mechanisms which might reduce the faith of the shooter in their weapon. I found this policy going back to the early 1920's. Which was probably when it was recognized that the low number M1903's had a high rate of receiver and bolt failures.
Out of battery slamfires end unpredictably, and I don't know all the failure mechanisms to an inbattery slamfire. I have no doubt an partially locked in battery slamfire would over accelerate the bolt to the rear, and that could have been what happened to Sammy's during his rapid fire sequence. An out of battery slamfire is far less controlled and if the bolt is pushed to the rear, at a full 50,000 psia, delayed only by its weight and an inconsequential operating rod spring, that bolt has a lot of places it can go. With straight back being only one possibility.
I believe it is only prudent to use the least sensitive primer consistent with reliable ignition, in a Garand type mechanism.
And always, wear your shooting glasses!
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