Reloading for M1A

[DelcoDave]

I just got my Springfield M1A and I want to begin reloading. I think I want to use the RCBS small base dies but I am not totally sure. If anyone reloads .308 for an M1A let me know what works the best for you. Also what Bullet & Powder type would you recommend.

 

[WNTFW]

DelcoDave,
You might want to hit the Moderator and move this to reloading.

I have never had to use a small base die for anything. Others believe they are necessary and they exist for some reason. Maybe start with the regular die and go to SB if needed.

Either way I would buy a case gauge and use it. The other thing is get good case lube in the first place.

 

[M1key]

Nix on the small base die.

Try 39.0-41.0gr of IMR 4895, behind Sierra 168 Match bullet, with Federal (or other commercial) brass.

 

[Slamfire]

I have 308 and 30-6 gages, cut by Gene Barnett which are a little out of the ordinary. He cut these gages with his chambering reamer. Standard cartridge headspace gages are cut with a special reamer that is wide in the middle. A standard cartridge headspace gage measures length, not “fatness”. A reamer cut headspace gage will show you if the case is too long and too “fat” for that chamber.

I have a number of 308 small base dies, and I still have my Lee standard die.

I sized a number of my match cases in the Lee die. All of them dropped in the reamer cut case gage. So, if you said you don’t need small base dies, you would be correct most of the time.

So now I had to scratch around trying to find cases that would prove my point.

These two cases are once fired range pickup brass that I found in my brass box. I had to go through about 20 cases before I found a set of really ballooned cases. On the right is the Barnett reamer cut gage.






If you notice one case has completed dropped into the Wilson cartridge headspace gage, while the other has not dropped into the Barnett reamer cut gage. This shows how much they have swelled up after being fired. Must have been a big chamber.

The second picture is of the fattest of the group after sizing in with Lee Die. I trimmed the thing to make sure that the case neck did not interfere with the throat in the gage.




Hopefully you can see that the case did not drop all the way in the case gage. At least on its own. It would have taken a good hard push to get that base all the way in.





This is after resizing in my RCBS small base die. I could not find the RCBS box, so the case/gage are sitting on a Redding small base box. However, that little additional sizing removed the interference fit.



Sometimes cases are so ballooned that even a small base die won’t reduce the case to factory dimensions. It all depends on what chamber the round was fired in.

If you are buying once fired military brass, 99% of that is now fired in machine guns. Machine guns have huge chambers.

I know it is extra effort to size cases with small base dies, if you use a good lube like Imperial Sizing wax or RCBS case lube, the effort is somewhat reduced. Still for all the extra bother involved in sizing with small base dies I'll do it for my Garands and M1a's. With those rifles I don’t want any resistance to chambering, I don’t want any delay to bolt closure. Because as the bolt stops and the lugs are turning, that darn free floating firing pin is just tapping the heck out of the primer.

As for bullets, well it all depends on what you want to do.

For match shooting I used 168 Match bullets out to 300 yards. At 500/600 yards I am using 175 SMK. You should use nothing heavier than a 175 grain bullet. I have buds who have used 125 grain bullets 200 yards SF and RF, and they did very well with them.

There is only one powder to use in a M1a, and that is IMR 4895. AA2495 is a copy, and H4895 is so close that I can't tell a difference across the chronograph screens.

A standard match load is 168 SMK 41.5 grains IMR 4895 LC cases, CCI#34, OAL LT 2.800"

 

[FlyinBryan]

not my thread, but very well done slamfire. enjoyed.

interesting gages too, as is the difference in color between imr and hodgdons.

 

[dawico]

My buddy has a M25 Whitefeather m1a and standard Lee 308 dies reload for it just fine. A medium charge of 4064 (can't remember the exact charge at the moment) with 175 SMKs or 178 Amaxes shoot easily under an inch through it.

 

[Slamfire]

not my thread, but very well done slamfire. enjoyed.

interesting gages too, as is the difference in color between imr and hodgdons.

Glad to be of help.

By the way, I was being dogmatic about IMR 4895. There are other powders that work well, IMR 4064 for one, but I prefer the shorter grained 4895 powders. My measure throws 4064 plus or minus a grain to a grain and a half, 4895 to plus or minus a half grain.

 

[FlyinBryan]

By the way, I was being dogmatic about IMR 4895. There are other powders that work well, IMR 4064 for one, but I prefer the shorter grained 4895 powders. My measure throws 4064 plus or minus a grain to a grain and a half, 4895 to plus or minus a half grain.

i would be tickled pink if 4895 powders measured like h322 in my particular measure. i also get my largest variables with 4895. (but its still the only powder i will load for our garands, 1944 and 1954 cmp rifles) my brother often shoots right around 1.5moa, even with his 60 year old eyeballs. 46.4g h4895 pushing 147g m80 or standard m2's.)

EDIT: THE ABOVE IS NOT AN M1A/M14 LOAD....

 

[desidog]

As alluded to by Slamfire1, 175gr is about as heavy as you want to go...heavier and you risk bending/damaging your op. rod.

 

[dogsoldier0513]

My M1As like WIN748, R-P match-prepped brass, Nosler 165gr. 'Ballistic Tips' and CCI 'Benchrest' primers.

 

[Curator]

I second what M1key posted. I alos use the Lee collet die and neck size only my carefully sorted R-P brass. My accuracy load is 40 grains of IMR 4895 with the Sierra 168 hpbt bullet. I have loaded this batch of brass 13 times and they are still going strong. No cracks or failure to feeds. I do use CCI Mil-spec primers and have reamed/uniformed the primer pockets to avoid possible slamfires.

 

[Welding Rod]

Any experiences with Varget in the M1A? With 150 grainers?

 

[stubbicatt]

Curator said: I alos (sic) use the Lee collet die and neck size only my carefully sorted R-P brass. My accuracy load is 40 grains of IMR 4895 with the Sierra 168 hpbt bullet. I have loaded this batch of brass 13 times and they are still going strong. No cracks or failure to feeds.

You neck size only for your M1a? With a collet die? Wow. This is the first I've heard of that actually working. I remember reading an article on the net somewhere about how small base dies and that full length resizing were very important in the M1a so that one would not get slam fires. Reading your posting in light of that article makes me wonder how easily your cases are sliding into your chamber, and whether you might not be running a risk here?

 

[Curator]

stubbicatt,

I have a Wilson headspace gauge and use it on my neck-sized cases. The 40 grain IMR4895 load is probably about 50-55K psi but it does not result in any case stretching in my "Loaded" M1A. I check case length every couple of reloadings. I have rejected a couple of cases but most pass with no problem. Cases slide in like new. Yes, I too have heard about small base dies, slamfires, etc. etc. I have reloaded for M1 National Match for 30+ years using a "partial size" technique without issue. I keep the chamber and brass clean and pay attention to the possibility of cases that might not chamber fully. The additional accuracy is a bonus but may be accompanied by a risk. YMMV.

 

[Slamfire]

I have a Wilson headspace gauge and use it on my neck-sized cases.

Good to see that you are using a gage.

I check case length every couple of reloadings. I have rejected a couple of cases but most pass with no problem. Cases slide in like new.

I assume your neck sized cases slide in the Wilson gage like new.

I must conclude that you have been assuming if a case would drop in a Wilson gage, then it must be OK.

If you did not know, Wilson gages are cut large between the base and the shoulder so you can insert fired cases and get the headspace of your chamber. A Wilson gage only measures length, not "fatness". If you ever had cases that were too fat to drop in a Wilson gage, then by God, that case was really ballooned.

I guess you missed the subtlety of this picture:


Both of these WRA cases were fired in the same rifle and neither has been sized. One case dropped right in the Wilson gage without resistance. The other case, the one on the right, that gage was cut with a finishing reamer by Gene Barnett. It is dimensionally correct for length and width same as a chamber on a properly cut and headspaced match barrel installed by Gene Barnett.

Notice that the case does not drop into the Barnett gage. That is because it is too fat. The other case would have had the same amount of case head hanging out. Either case would drop in the Wilson gage, just as you see in the picture. But that does not mean there would not be resistance on chambering, because both cases are fat.

Just because a case drops in a Wilson gage does not remove the possibility that it will be an interference fit in the chamber

This picture shows the point at which the firing pin tang touches the receiver bridge in a M1a. The items were a new M1a receiver and a like new CMP GI bolt. The firing pin is fully forward but you can’t see it. I pushed the bolt forward in this receiver until I felt the receiver bridge contact the firing pin tang. Then I took the picture.

This is right at cam down, that is the bolt is about to rotate in the recesses of the receiver and cam down.

I believe the bolt and firing pin have reached the highest forward velocity at this point.

The firing pin is free to move up to this point, and in fact, until the bolt rotates a bit further, some of the firing pin tip will continue to stick out through the bolt face.

Gas guns have a bit of margin in them, if a case is a little long, or a little fat, there is enough momentum in the system to “crunch fit” a cartridge in the chamber. Of course if the case is too long or too fat, a jam will result. We read posts all the time where shooters are having jams due to cases that won’t chamber.

While the mechanism is resizing these cases, that free floating firing pin is rebounding off the back of that primer, at the highest forward velocity in the system. Incidentally the lugs are not necessarily engaged, as you can see.

That is why you never, ever, ever, want to delay lug engagement in a M1a or M1 Garand mechanism.

It is good practice to use the least sensitive primer you can find, and the CCI#34’s are sold as “Mil Spec” (but only been available around 1999) however, primer sensitivity varies.

If you read George Frost’s book on reloading you will see that primer lots have “all fire limits” and “no fire limits”. There is a significant drop distance difference between the two limits. Lot acceptance criteria allows a lot to be accepted if a few primers ignite at the lowest drop distance. The probability of primer ignition is never zero.

Yes, I too have heard about small base dies, slamfires, etc. etc. I have reloaded for M1 National Match for 30+ years using a "partial size" technique without issue.

So, for the last thirty plus years the only thing that has prevented you from having an out of battery slamfire, or an in battery slamfire, has been primer insensitivity.

You have been lucky. I have plenty of accounts of out of battery slamfires in Garands with military ammunition, only one with military ammunition in a M14, but that may be due to the greater number of Garands in civilian hands. I am aware of a number of out of battery slamfires in M1a's with Federal primers.

What you are doing with partial sizing is delaying bolt closure, because you are requiring the mechanism to size the case to the chamber, and while this is happening, the firing pin is rebounding off the back of the primer at the highest velocity possible in that mechanism.

All it will take is one overly sensitive primer in one lot of primers and you will have an out of battery slamfire.

I hope it does not happen to you but you have certainly increased the odds having one by your reloading practices.

 

[mshootnit]

So for the rest of us that can't have Gene ream us a gauge which one to use for "fatness"?

 

[Slamfire]

So for the rest of us that can't have Gene ream us a gauge which one to use for "fatness"?

Actually you can have a “reamer cut gage”.

When Frank White of Compass Lake Engineering installed one of his barrels on my Space Gun upper, I asked him to cut me a chamber gage using the same reamer.

It cost me all of $35.00.

You can call either Frank, Teresa, or Bunny at: 850-579-1208

Their web site is: http://www.compasslake.com/

Compass Lake Engineering:
719 White Drive
Alford FL 32420


Still this is still avoiding the question of how do you check “fatness” without a dimensionally correct chamber gage.

And I really don’t know the best way, or if any of the work arounds can be judged reliable.

If you said “use the rifle chamber”, that has its own issues.


One issue about using the chamber as a gage is that you have to strip the bolt of its extractor and ejector. You can’t have the bolt under operating rod spring tension or you won’t feel anything. Because this is such a bother, I don’t do it.


I believe that pushing a case into the chamber without a bolt might provide false impressions that the case is properly sized. This is because you really don’t have a way to measure how much of the case is sticking out of the chamber when the case bottoms out.


This can be shown in this picture. This is one of those ballooned WRA cases and it was full length sized in a Lee Die. It would drop down to the proper size length height in the Wilson gage, but in the reamer cut gage it sticks. It does not stick by much, but I promise you, that little amount out of the gage is enough to give you an out of battery slamfire in a Garand in 30-06. Because I have experienced them with federal primers. One the second slamfire the group of remaining cases were checked by the gunsmith and some were just .002” to .003” over length.




Still , if you are not going to use a gage, this might be better than nothing.

I use small base dies on all of my gas gun calibers because that reduces the risk of having a “fat cartridge”.

Reducing slamfires is a risk reduction process, and this is what I do:

1) I full length resize all my cases with a small base die.

2) I size to gage minimum.

3) I ream primer pockets to depth to reduce the chance of a high primer.

4) I prime by hand and verify that all primers are below the case head.

5) I use the least sensitive primers on the market. CCI claims that their #41’s and #34’s are “Mil Spec” and that is what I use. I don’t use Federals as they are the most sensitive primers on the market and I already have had two out of battery slamfires in Garands with Federals. If the mil spec primers are not available I use CCI standard as everyone complains how “hard” they are, so I am hoping that maybe they are “less sensitive” than other brands.

Even after doing “everything right” there is always the statistical chance of a slamfire, so always be sure nothing is in line with your muzzle when you chamber a round.

This video of a Tavor slamfire is an object lesson in slamfires.

Notice how many rounds the guy fires. If he had a mechanical problem he would have recurring slamfires, but he did not. When you see the slamfire, notice that the finger is not on the trigger. He was running Federal American Eagle (federal primers) and Winchester ammo. Winchester redesigned their primers in 1999 to make them more sensitive.

This weapon slamfired in battery. The risk with Garands and M1a’s, unlike AR actions, is that they will slamfire out of battery.

http://www.youtube.com/watch?v=_cv7BI3wGWA

 

[JNewell]

I have been reloading since the very early 1970s, but I have never had the urge to reload for a semi-auto rifle. With loads like Federal GC Match, there isn't much upside in terms of accuracy, and you can still buy quality generic ammo cheap enough that there isn't much upside, if any, in terms of cost. And, as this thread has made clear, there is a lot of need for real care and significant room for serious foul-ups.

 

[bfoosh006]

DelcoDave... read/save/print these first two articles from the link, I use them all the time..http://www.zediker.com/downloads/m14.html.

Glen Zediker writes GREAT books and has shot for decades.