Ramshot TAC for M1A/M14?

[Round Dial]

A few years ago I bought some loaded ammunition at a gun show for use in my M1A. For a variety of reasons, I haven't shot the ammunition yet. I recently got into reloading and learned about port pressure issues with service rifles. I have read to only use powders with burn rates in between IMR 4895 and 4064. TAC is listed as one powder faster than Hodgdon 4895 in both my Sierra manual and on Ramshot's website:


http://www.ramshot.com/powders/ (http://www.ramshot.com/powders/)

The ammunition came with a printout of the load data from QuickLoad. It was loaded as follows:

Sierra 168gr HPBT MatchKing 22 (appear to be moly)
LC Brass
42.0 gr of TAC
COAL 2.800"
No primer listed

Is this ammunition safe for use in my M1A?

[Unclenick]

The specified load is likely to be safe. Compared to a 4895 load the gas port pressure is actually lower. However, you should be aware that QuickLOAD predictions are only accurate when you have the fired case water capacity for the case coming out of your own gun's chamber. QuickLOAD also assumes the mildest possible primer is used, while military primers are basically magnum primers for good cold weather performance. So, the QuickLOAD predictions for pressure are likely to be low unless your chamber is big enough to allow the case to expand significantly. Peak pressure is dependent on the volume the case expands to in the chamber, and not what it is after resizing.

Also, unless this guy was an experienced commercial loader, I would hesitate to use the ammo at all. It is an old and good rule of thumb not to use handloads made by others since you don't know how careful they were or how good the equipment used was if you weren't there and witnessing the loading process for yourself. Personally, If this was just some guy at the show and not a commercial reloader, I would pull the bullets using an inertial bullet puller (so as not to damage the bullets). I would weigh the average charge coming out and set the powder aside and inspect it to make sure it looks like TAC. I would knock the load way down, say by half (in case it is actually something faster than TAC accidentally used) and test one round. If it is a complete wimp load that fails to cycle the action, I would then figure the loader wasn't too far off the beam, and work the load back up from about 10% below the weighed average you measured, looking for an accuracy peak.

I don't mean to alarm you, but stranger-built handloads are a case where you need to verify them. It's not all that much effort compared to recovering from having a gun damaged.

[Slamfire]

UncleNick has some good points about not using someone reloads.

I have never used TAC. Being a little faster than IMR 4895 is OK. IMR 4895 is the baseline powder. If you are using it, everything will be fine. I knew of guys with match M1a's who had problems with IMR 4064. Probably due to those huge gas port holes that barrel makers put on their aftermarket barrels. (Check it out, GI gas ports were big enough, compare your aftermarket barrel. Mine were drilled larger!)

Slow is bad. Slower is a lot worse than faster. Slow burning powders will raise the gas port pressures. Which will accelerate the operating rod too fast. Folks will experience ripped cases rims, and sudden onset case head separation because the action is being opening too early in the pressure curve.

Faster is OK as long as we are not talking about something like Bullseye. In fact, in some ways, faster might be better. Assuming the load does not exceed 50,000 pounds, a faster drop off in the pressure curve would be good, as long as the action cycles.

But I don't have kegs of experience with much of anything but AA2520, IMR 4895/AA2495 and recently H4895. I talked to a guy who had a lot of experience with vihtavuori powders. At the time he was the person vihtavuori referred me for technical questions. I had VV-N135, a relatively fast powder. He stated that N135 would "beat" up a M1a. I was not sure what damage was being done, and his database was some military rifle team's experience. He recommended N140, a little slower. I knew guys who shot N135, they never complained about anything but the price.

I have used about two pounds of estate sale IMR 3031 in my bolt rifles and M1a's. The stuff is a little faster than IMR 4895 and shot well. I never heard of anyone using it other than in bolt rifles, but my M1a functioned fine.

[Unclenick]

I am unaware of a problem with any of the powders SlamFire1 just mentioned. I've never heard of N135 causing op-rod wear in the M14-type action. However, I have heard complaints from a very experienced lever gun shooter that 3031 tended to be, as he described it, "peaky", tending to heat the gun up fast and to be sensitive to charge precision. I'm not at all clear why that should be true? It may just be an artifact of the problem that any time you go to a faster powder you tend to leave more empty space in the case which allows more pressure difference due to how far the powder has settled from the primer at the moment of ignition. It is a complex subject that depends on a number of factors. The story about problems with N135 may be true for similar reasons as with 3031, but it could also just be a coincidence based on what age the guns happened to be when the trial was started? Even experienced people can be fooled by the inter-dependency of variables they've mistakenly failed to isolate.

It occurs to me to mention that the Sierra manual has something like 17 pages on loading for gas guns. It wouldn't hurt to read that if you can get hold of a copy?

[Round Dial]

OK, I'm a little nervous taking gas-gun reloading advice from a guy named SlamFire!

Thanks for mentioning the section in the Sierra manual. That's where I first read about port pressure issues. They really did put some good information in there.

If I knew then what I know now, I would not have bought the ammunition. I was looking for some affordable bulk match ammunition. I have 300 rounds of it, so I don't want to through that much money away. He had/has a business name and appeared to be a small outfit and not just some smoe with a press. I haven't been able to find a website for him, but he is listed here as Performance Ammunition: http://www.shooting-hunting.com/results.html?Keywords=Targets&FoundID=525

I like your idea about pulling a couple of rounds apart. I don't own any TAC to compare it to, but I could weigh the charges and do some basic QC type inspections.

Thanks again.

[Slamfire]

OK, I'm a little nervous taking gas-gun reloading advice from a guy named SlamFire!

It is hard to beat the school of hard knocks to teach one the lessons of life!

After two bad slamfires in Garands, one that blew the back of the receiver off, I learnt some real facts, and have become very particular in loading the things.

One real fact: Don't use "sensitive" primers in reloading for these things.

Post 7 in this thread is what I do when I reload for Garands or M1a’s. On the third barrel of one match M1a, and nary a slamfire since I followed my advice.
http://www.thefiringline.com/forums/showthread.php?p=2998115#post2998115

[Round Dial]

It is hard to beat the school of hard knocks to teach one the lessons of life!

Ain't that the truth.

SlamFire, ya know I was just teasing you about your name right?

I'm going to start reloading 308 in the next month or so (which really means 3-4 months) and ran into your post in that thread the other day. I took some notes on what you said. Thanks for the advice. You put some good info in there.