M1A Questions

[splotch]

I just bought a Springfield M1a based on the sticky using it with cast. I started to read the lit that came with it and holy cow they make it seem that if you don't use factory loads you will at sometime have a slam fire. The web is no better giving the impression that eventually you will have one if you reload for it. Not only that but parts wear will get you if the reloads don't. First is this a bad choice for reloading with cast? Is it inevitable that you will have a slam fire? And how would you break in the barrel for cast bullets?

[joesig]

It's a great choice for cast or mil surp. Check out http://m14forum.com/ for other M1A details. For primers I am partial to CCI 34 but the biggest thing to watch is that the primer is below the case head. A proud primer is guaranteed to slam fire. A quick check with your finger will tell you if it is safe or not.

[ShooterAZ]

Just make sure you seat your primer all the way flush or a tad below and you should never have a slam fire. My M1A had never seen a factory load, and no slam fires. This is a misnomer.

[Scharfschuetze]

I've worn out barrels in M1As and M14 NM rifles. Many of the rounds fired were reloads using all brands of primers without an issue.

If it is of concern to you, CCI markets a primer with an extra hard cup designed for semi-auto and auto rifle use.

The M14/M1A design uses mechanical features to block the firing pin during chambering until the bolt is fully in battery. As noted above, a high primer may be susceptible to a slam fire no matter what safety features a rifle has. One of our members wrote of a slam fire when he was loading single shot when the op rod slipped from his control and slammed forward out of control, but other than reading that, I've not seen a slam fire ever in over 40 years of shooting the M14/M21/M1A rifles on numerous rifle teams, training and deployments.

The design uses friction from the lips of the magazine to slow the bolt velocity when chambering a round. If single loading, be sure not to just let the bolt fly forward without some friction to preclude wear and that possible slam fire.

[country gent]

I have 2 M1As/M14s built to national match standards, Heavy stock, front and rear lugs added, modified hand gaurds, gas system unitized, triggers tuned and lightened. Both are on their 3 krieger heavy stainless barrel. Not excessive wear but roughly 20 years as a NRA service rifle competitor and High Master level shooter. In all that time and rounds ( close to 30,000) I have replaced 1 extractor and 2 firing pins. Ive never had a slam fire and only seen one in all this time. 90% of this was handloads duplicating M852 match ammo with 168 grn bullets. Watch and check every round of your reloads for high primers, Make sure the shoulder is "bumped back" .002-.003 and fully sized so it chambers easily. When single loading clip round into mag and close bolt chambering round from mag as this slows the bolt the same as the rifle cycling. Putting the round into the chamber and letting bolt slam gives it alot of extra OOmph. Half the rounds fired in a High Power match are single loaded. You want your ammo to chamber freely with no resistence or sticky spots. The M1A was a very reliable and accurate rifle. Mine were shot to 1000yds when I was competing. Load appropriate ammo and use established practices and chances are you will never have an issue. The only "weak spot on the M1A ( also the Garand) is the lack of bedding surface area, Stock will go about 1500rds before accuracy starts to suffer. This depends on how often you remove it from the stock, pressure of your loads, How diligent you are keeping solvent from bedding,

[BruceB]

The last step in loading for my M1A is this:

EVERY SINGLE ROUND is tested in a cartridge gauge.

When performing this routine, it's very easy to both look at the primer, and also to run a finger across the case head to FEEL the seating depth of the primer.

Pay heed to the cautions about letting the bolt run forward when single-loading. Let the bolt move about a third of the way forward under control, and then let it go. It will still have enough inertia to close and lock, while the extractor snaps into the case groove. However, the bolt speed will be greatly reduced, and the remote chance of a slam-fire will be virtually eliminated.

[M-Tecs]

Scharfschuetze and country gent have it right. As team armorer and a competitor I have not even seen a slam fire not related to a high primer.

[splotch]

Any hints as to breaking in a barrel for cast bullets

[Scharfschuetze]

Is the m1a's oprod as sensitive to different ammunition as the m1 garand?

Joshk,

No, it doesn't seem to be as it is much shorter and is also straight so that it does not flex like the M1 oprod. I think that's where M1 rifles get into trouble. The purposely bent (follows the contour of the barrel) oprod can only flex excessively so much or so many times from the wrong powder selection before it is damaged.

I had a vented gas plug on my M1A (built up like Country Gents' post above) and I never had any issues with the oprod over the life of a couple of barrels.

The M14/M1A gas cylinder is also self venting after a short travel of the piston and releases any high or residual pressure out of the cylinder at the 6 O'Clock position.

I've never used anything slower than 4064 in my 7.62/308 M1A loads. Most of my fellow competitors also used mid range powders like Reloader 15, 4895 and 4064 so I have no idea how the oprod would stand up to a diet of 4350 or 4831. The case's limited capacity probably argues against such slow powder in it to begin with other than perhaps with some cast boolit loads. My guess is that the opening and closing cam surfaces in the oprod (where the roller bearing on the right bolt lug operates) would probably eventually show some signs of wear from excessively hot loads.

[BruceB]

Any hints as to breaking in a barrel for cast bullets

All I did with mine when it was new was fire about 500 Sierra Matchkings through it. Could have used less-expensive bullets, but it was also a chance to see what the rifle could do with excellent bullets. Answer: VERY close to MOA at 100 yards, even with shaky vision and the issue iron sights.

I did NOT clean after every five-ten-twenty-however many rounds. The rifle fired whatever I thought reasonable on any given day, and was cleaned afterward.

This process didn't take long, as I was eager to get to the REAL shooting.... cast bullets.

Once the cast-bullet research started, the rifle was cleaned VERY rarely, and I mean rarely! The action got attention when it became noticeably fouled, but the barrel was pretty well left untouched. I think the results speak for themselves.

Gunmakers typically try to cover their ASSets when writing the manuals. Don't worry about it.

[country gent]

The op rod isnt as senitive to slow poders as the garands but the timing of the rifle is. The ported gas plugs help with this and adjustable ports are even better but The rifle takes a hammering with extra heavy bullets or slow powder. I also utilized IMR4895, reloader 15, and H 4895 with 155 grn to 175grn bullets. Mostly 168s as that was the ticket back then. I would do a break in with jacketed bullets fire one round and clean 5 times, check for jacket fouling if present repeat if not 2 rounds and clean 5 time check for jacket fouling if prestent repeat if not 10 shots and clean to total of 100 rds. This will smooth the barrel and help "alighn the flow marks into proper direction. You might want to even repeat an abreviated run with cast bullets even after this. What model did you buy? What barrel does it have on it 1-10 1-12 twist 4 groove 6 groove Gi profile medium heavy or full heavy? Stainless or carbon steel? Lugged or unlugged reciever? Most are very accurate and dependable.

[Ken in Iowa]

Excellent advice above.

We used thousands of rounds of M14 ammo loaded with Remington 7 1/2 primers, 40 gr of IMR 4895 tipped with a Sierra 168. We always used a magazine to single load - after a shot clip a fresh round in the magazine and release the bolt when ready. No slamfires were experienced.

A magazine is required to make the bolt lock back after the last shot, so there is no real advantage not to shoot with one.

I will look with interest how your cast experience goes.

[SlamFire1]

I just bought a Springfield M1a based on the sticky using it with cast. I started toread the lit that came with it and holy cow they make it seem that if you don'tuse factory loads you will at sometime have a slam fire

.

Slamfires are rare, rare enough that some people deny that they ever happen.

The Garand mechanism does not have a positive means of holding the firing pin back, that so called "safety bridge" is there to retract the firing pin. As such, the firing pin tang does not touch the thing until the last 0.006"of forward travel.

I have a paper copy of a military test report from the early 60's. The military was production article testing Harrington Richard M14's. M14's made at SA were used as control rifles. Parts were gaged, down to chrome lining thickness I think, parts checked for interchangeability, then HRA and SA rifles were endurance tested to 6000 rounds each. One SA M14 slamfired out of battery prior to shooting 6000 rounds. I added up the total round count, and based on the number of rounds fired, and the out of battery slamfire, the chance of a M14 slamfiring out ofbattery with mil spec primers is about 1:35,000 per shot.

Primer sensitivity is the primary cause of slamfires, in battery and out of battery. As long as that free floating firing pin can hit the primer, the possibility of ignition exists. Given that primer sensitivity varies, sometimes a sensitive enough primer will ignite.

The riskiest condition for any Garand type mechanism is a tight case and a sensitive primer. If the bolt has to slow down to crunch fit a cartridge to the chamber, that free floating firing pin is rebounding off the primer. If the lugs are not in engagement, an out of battery slamfire will happen if the primer is sensitive enough to ignite.

My reloading advice for these mechanisms is to full length resize all cases, and preferably, size using a small based die. Sizing dies should be set up with Wilson type cartridge headspace gages and the cases should be sized to gage minimum. Sizing cases as close to factory dimensions as possible, will reduce the risk of the case binding in the chamber and delaying bolt closure.

Cast bullet shooters like to seat their bullets into the lands. This is bad practice for Garand type mechanisms. I know of one cast bullet shooter who did this until his Garand slamfired out of battery and blew off the receiver heel.

The next important item on the list is to use the least sensitive primers on the market, which are the mil spec CCI #34's or Tula 7.62's. Commercial primers are more sensitive than the military type and the slamfire probability goes up with more sensitive primers.

Ream primer pockets to depth and ensure that every primer seated is below the case head.

Never ever place a round in the chamber and drop the bolt on it. You want to slow the bolt, and thus firing pin, by pushing rounds into the magazine. The friction it takes to strip the round out of the magazine will slow the bolt a little bit.

It used to be that people denied AR15's slamfired. Prior to Bushmaster breaking the Colt monopoly there were just not that many AR15's on the firing line. Now there are lots of them and there are lots of slamfire reports. It used to be that you could load your rifle on the shooting stool, in the standing stage, during NRA highpower competition. I used to place the butt of my Garand/M1a on the shooting stool and press a round into the chamber. The muzzle was of course pointing up. Never heard or saw a slamfire when loaded this way. Then the AR15 became the dominant service rifle, and AR15 shooters loading their rifles by placing the muzzles on the shooting stool, placing a round in the chamber, and then hit the bolt release. Enough AR15's slam fired through the shooting stool that this practice was disallowed. You can imagine the shrapnel exploding out on the firing line as a 223 round goes through the shooter's ammunition, magazine, tools, etc. One friend of mine was almost shot by a Junior at Camp Perry. Junior was loading his AR15 almost parallel to the firing line. I have seen one guy doing this, bringing his AR15 up to his face during the standing stage, dropping a round in the port, and hitting the bolt release. I think Junior was doing the same. Anyway Junior's rifle slamfired in battery, the round went in the air between my friends arm and body as he was aiming in the standing position.

If you shoot enough Highpower competition you will see or hear of slamfires in the AR15 mechanisms. Almost no one shoots Garands or M1a's in competition, but back in the day, I met people and heard their Garand/M1a slamfire stories. Every account I heard had one common factor: Federal match primers, the most sensitive primers on the market.

Even though I follow all my reloading practices, I decided for a little more slamfire insurance. I sent my Garand bolt off to Roland Beaver and had him install a firing pin spring. This spring is quite stiff and keeps the firing pin from rebounding off the primer. I sent it off on a Monday and got the bolt back next Monday.