7.62x51 NATO (.308 WCF) in the Springfield M1A

[overbore]

Larry, First, unless you can call my attention to any contrary publication on the M1A that is cited as a standard reference work by the experts at the M14 forum, you and I must agree that the Author is an expert on the RIFLE. With full an open respect to your cast bullet expertise, I see nothing in your writings referencing Port Pressure, the crux of my concerns.

Let us get to the core issue and my priorities I attach to any load from my 50 + years of handloading experience;
1. SAFETY, Shooter and Rifle

2. Accuracy

3. Ease of duplicating

With my criteria established, here are the author's AFETY concerns:

"Powder and Port Pressure

Yet another safety issue: which propellant to use. (Yes, there is a time when everyone gets to just go shoot their rifle, coming soon.)
For the M14 to function as a self loader, gases from firing are bled into the gas
cylinder from a port hole in the barrel; these gases are fed through a corresponding hole in the piston, which has a forward facing (into the cylinder) hollow end. When sufficient pressure has accumulated inside the cylinder, the piston moves rearward, the gas port inlet hole misaligns with that in the barrel and shuts off the flow, and the action stroke commences. The piston butts up against the operating rod at rest (before firing) so that when the piston moves to the rear it moves the op rod back, which, being connected to the bolt, opens the bolt and cycles the action. Legions of linkage.
Design specs call for the vicinity of 12,000 psi port pressure. The level of pressure that exists when the majority of gas reaches the barrel port is port pressure. Staying within this figure is easy provided we know propellant burning rate rankings. Port pressure is not the same as chamber pressure, nor are there direct corollaries: low chamber pressures do not necessarily mean low port pressures, and vice versa. Slow burning powders, which generally test to lower chamber pressures in .308 W., escalate port pressures to well above the limit for the M14. This has to do with the volume inside the barrel, which is increasing in front of the case as the bullet travels outward, and the amount of gas pressure behind the bullet during this journey, which can be greater with a “late blooming” powder. When port pressure exceeds specs, “blooms” at the port, the piston moves at excessive speed, which also moves back the op rod and bolt too quickly and forcibly. The gun gets battered or broken and the cases take that much more abuse due to faster unlocking of the bolt. I don’t know what port pressures are with all available gun powders, but that doesn’t matter as long as I know this: the burning rate that defines the upper limit is IMR® 4064. Use nothing slower. Ever.
This is not to say it’s necessary to use a “fast”powder. Then the same standards apply here as for most everything else. Fast powders (like H322) can overblow chamber pressures before producing adequate velocity, or port pressure, in a .308 W. case. However, anyone who sneezes dust might remember that one of the all-time greats in this use is IMR® 3031 at 39.5 grains (this was original in the original black and white boxed Federal® Match that shot so well). The time-proven performer in this rifle is one of the “4895s.” There are at least three and all are suitable, even though they’re not precisely the same. The 4895s are excellent, flexible performers: there’s a wide range of charge volumes that still produces top accuracy — just tune the speed. This, by the way, may be the only easy part of handloading for an M14: finding “the load” is not difficult. That’s been done."

Satisfy the port pressure concerns with listed loads and we are in sync.

Cordially,
overbore

[BruceB]

With all due respect to the "published wisdom", and I DO respect it, AS FAR AS IT GOES, the cited authors to date have apparently done zero research on cast bullet loads in the M1A/M14 platform.

This is not astrophysics. Anyone who is familiar with the M-14 operating system KNOWS that port pressure is demonstrated by the ejection pattern, the fall of the fired cases. In using ONE rifle, and only one rifle, variations are kept to a minimum, and involve only the ammunition.

The firing of around 500 rounds of the "published wisdom"'s standard load, 41.0/H4895/168 Matchking/CCI#34 in the new rifle gave me a very good idea of how the rifle functioned, including ejection, velocity, and pressure. I say "pressure", because the only primers ever used in the rifle, over 5000 to date, have been CCI#34 of the same production lot. As my load work progressed, I became quite confident in reading pressure from primers, at least to the extent of saying that the HOTTEST load fired to date in my rifle is the standard 41.0/4895/168 Matchking.

The ejection pattern changes along with port pressure, a point that was raised and expanded-upon in the course of this thread. It should be evident that cases of the same manufacture, same weight, and same loading history, and fired with CAST bullets, which land in the SAME AREA as cases fired with the "standard load", were driven by port pressure similar to that of the standard load. I repeat: a load which lands the cases in the same vicinity as does the standard load, is operating at PORT pressures similar to the standard load.

The burning speed of the powder is IRRELEVANT as long as the chamber pressure is safe and the port pressure is within normal operating limits.

An "authority" is NOT an authority in fields other than those in which he has some meaningful experience.

[Larry Gibson]

Overbore

You might want to pay attention to what Bruce says, he has learned the facts of the matter. Mr. Zediker is correct in his statements as you quote him however he is referring to high pressure high velocity jacketed bullet loads. This thread is concerned with cast bullets of light to heavy weight at a considerable less pressure than the 55-60,000 psi loads Mr. Zediker refers to. The very reason to use slow burning powders in cast loads to keep the port pressure at a functional level is explained very well by Mr. Zediker. You however are apparently misconstruing what he says. You also are misconstruing your experience with an M1 with what happens with a M1A/M14 system. You are essentially comparing apples to oranges.

FWIW; my first experience with an M14 was in basic training in '64, I qualified Expert. My training with M14s and m14E2s continued through infantry training and I used one for a while in Viet Nam. When I say "used one" I don't mean I was issued one and just carried it around either...I actually "used" it. I continued with competition using military M14s and my own M1As. I made Master HP classification with one shooting over the real course not a reduced course. I also made Master Classification with one at long range HP (600-1000 yards). I also manage a state championship in LE competition with an M1A and I also was a state short and long range IPSC champion with one. I have given combat instruction to US soldiers and foreign soldiers on the M14. I have built many match rifles, rack grade rifles and M14A1s over the years. I first reloaded for the M14/M1a in '69 and have loaded tens of thousands of round since then. My first cast bullet loads for the M1A and m14 were in '76 and I've shot thousands of cast bullet loads through numerous M1A/M14s since then. I still own two M1As, both rebuilt because I couldn't count the number of M1A/M14 barrels I've shot out. Now that may not make me an "expert' as Mr. Zediker is because I do not post over on that forum but then there are many forums I do not post on. I do not claim to be an "expert" here but I do think I know what I am talking about in this instance. Attached are a couple pictures of me with M1A/M14s over the years.

If you pay attention to Bruce, who has done his homework on loading cast bullets in the M1A, you just might learn something that Mr. Zediker might not know.

Larry Gibson

[acemedic13]

I have been loading cast for mine with mixed results. My first few rounds did not have enough ass on them to eject. So of course I came here and read through this site and it all worked out. Thanks AGAIN Bruce for putting experience out there and not an opinoin. Nothing like real range data to make it all work out.
I am damned sure no expert with the rifle. But we still pack em' at work and they still knock Americas enemies stone dead. It is still the best platform out there......Now there's an opinion.....


Great pictures Larry.

[joshmb1982]

sorry. i havent gotten past the first page here yet. but at these velocities on the first page(11-1500fps) was the rifle cycling properly, or did you turn the gas port off and cycle it as a straight pull bolt action?

[BruceB]

Josh;

Unless specifically mentioned, as with the 4198 loads, the rifle functioned as a semi-auto with all loads.

I'm not interested in using the M1A (or M1, for that matter) as an awkward straight-pull rifle. There are plenty of manually-operated rifles around here to satisfy any need I have for such rifles.

It's really past time for me to get back to the M1A project. Some new moulds are now on-scene, and many possible combinations still remain to be tried.

[StarMetal]

Overbore

You might want to pay attention to what Bruce says, he has learned the facts of the matter. Mr. Zediker is correct in his statements as you quote him however he is referring to high pressure high velocity jacketed bullet loads. This thread is concerned with cast bullets of light to heavy weight at a considerable less pressure than the 55-60,000 psi loads Mr. Zediker refers to. The very reason to use slow burning powders in cast loads to keep the port pressure at a functional level is explained very well by Mr. Zediker. You however are apparently misconstruing what he says. You also are misconstruing your experience with an M1 with what happens with a M1A/M14 system. You are essentially comparing apples to oranges.

FWIW; my first experience with an M14 was in basic training in '64, I qualified Expert. My training with M14s and m14E2s continued through infantry training and I used one for a while in Viet Nam. When I say "used one" I don't mean I was issued one and just carried it around either...I actually "used" it. I continued with competition using military M14s and my own M1As. I made Master HP classification with one shooting over the real course not a reduced course. I also made Master Classification with one at long range HP (600-1000 yards). I also manage a state championship in LE competition with an M1A and I also was a state short and long range IPSC champion with one. I have given combat instruction to US soldiers and foreign soldiers on the M14. I have built many match rifles, rack grade rifles and M14A1s over the years. I first reloaded for the M14/M1a in '69 and have loaded tens of thousands of round since then. My first cast bullet loads for the M1A and m14 were in '76 and I've shot thousands of cast bullet loads through numerous M1A/M14s since then. I still own two M1As, both rebuilt because I couldn't count the number of M1A/M14 barrels I've shot out. Now that may not make me an "expert' as Mr. Zediker is because I do not post over on that forum but then there are many forums I do not post on. I do not claim to be an "expert" here but I do think I know what I am talking about in this instance. Attached are a couple pictures of me with M1A/M14s over the years.

If you pay attention to Bruce, who has done his homework on loading cast bullets in the M1A, you just might learn something that Mr. Zediker might not know.

Larry Gibson

Little hijack here.

Larry, I'm working on my French M14, the MAS 49/56. I was patient and waited for a KVAR scope mount for it and finally got one. My rifle was rechambered to 308 so stay tuned we're going to see what she can do.

Joe

[Larry Gibson]

A "French M14"....rather insulting comparison to say the least. The M49/56 has little to nothing to do with or in comparison to an M14. The french did hijack the trigger mechanism from the M1 Garand though. Otherwise the M49/56 has more in common with Ljungman M42, the Tokerev and the FN. No doubt with with cast bullets your velocities will be high and your accuracy will be sub moa as usual, I can hardly wait.

Larry Gibson

[StarMetal]

A "French M14"....rather insulting comparison to say the least. The M49/56 has little to nothing to do with or in comparison to an M14. The french did hijack the trigger mechanism from the M1 Garand though. Otherwise the M49/56 has more in common with Ljungman M42, the Tokerev and the FN. No doubt with with cast bullets your velocities will be high and your accuracy will be sub moa as usual, I can hardly wait.

Larry Gibson

Larry,

I'll answer you statements here in the Military Rifles thread as not to hijack this one further.

Joe

[joshmb1982]

im now working on the third page here and it looks like your still using sraight WWs?? have you tried any other alloys pushing them a little faster?

[joshmb1982]

wow. what a read. i just finished all 6 pages. thank you bruce b for taking the time for all that. were your medical issues resolved i hope?? i have quite a bit of imr 4064 on hand. did it ever turn out a decent loading for you?

[fatelvis]

I seat both 311466 and 311467 to the same overall length, as they have identical nose shapes. I discovered yesterday that the length I've been using is TOO LONG to allow loaded rounds to be extracted from the chamber....they leave the boolits jammed in the throat!

Bruce B, I'm in the process of loading some 311466s for my M1A, and I know you gave up on this bullet due to live round ejecting problems, but I was wondering what OAL did you settle on that worked the best on target, before you scrapped it? Thanks-

[fatelvis]

So what load ended up producing the best groups, and operating the rifle reliably?

[Splatter]

So what load ended up producing the best groups, and operating the rifle reliably?

What an excellent question!
Or how about the top 3 loads, please?

[BruceB]

Gents;

All the info is contained in the thread, including group sizes and functioning data.

The vast majority of the loads work fine in MY rifle.

I mostly wanted to get a wide variety of loads published to give others a place to start, and it's up to each individual to determine what works for his own rifle, both for function and accuracy.

Accuracy results in MY rifle are just that....YOUR rifle may be entirely different in its tastes, and YOU will have to find out.

I'm hoping to re-start some M1A test loading soon, and info will be posted here in the same format I've used so far.

Best of luck to y'all.....

[longrifle]

after all the pb shooting in the m1a how does the gas system look when cleaning, how is the lead build up in the bores.
I understand shooting lead in levers, and bolts, but not gas system firearms that were designed for copper bullets.
can anyone post a pic of a gas system of a semi auto after shooting a couple hundred rounds, and how many rounds can you shoot till failure of the gas system or firearm to reload.
I would be willing to try shooting lead in a sks but not my 1500 m1a the thought makes me shutter.

[BruceB]

[QUOTE=longrifle;1147069]after all the pb shooting in the m1a how does the gas system look when cleaning, how is the lead build up in the bores."


NONE.

"Can anyone post a pic of a gas system of a semi auto after shooting a couple hundred rounds, and how many rounds can you shoot till failure of the gas system or firearm to reload."

In my M1A there is NO metallic fouling in bore or gas system even fter SIX hundred consecutive rounds. This was mentioned in the thread...did you read it? It was still functioning perfectly after those 600 rounds.

"I would be willing to try shooting lead in a sks but not my 1500 m1a"

I've never loaded cast bullets in an SKS. MY "$1500 M1A" loves cast loads. What's the problem?

[nicholst55]

I think longrifle needs to read the thread Old Wives Tales and Misinformation.

[fatelvis]

Hey Bruce, have you tried experimenting with 8208 yet? I've been doing good with ~24 grns 5744 under a 311466 in my M1A, but I have 8lbs of 8208 XBR staring at me from the powder locker. Hmmmmm.

[longrifle]

like I said before its your 1500 dollor gun, and when people read this and anyother post that gas operated firearms can safely shoot lead and not damage the firearm or potentially damage anything else I can only hope there is enough common sense to NOT USE LEAD in there fire arms. old wives tale or not
Use lead in a firearm ment for lead then you don't have to worry about old wives tale and becomeing a Darwin award winner

just my 2 cents