M1A brass and dies question

[Finarfin]

I'm very happy to report that I have acquired a new Springfield M1A. I can't wait to disregard the user's manual and start loading for it. I will probably start with some jacketed loads.

I have seen it mentioned that some use the thicker military brass and size with the rcbs small base x die. Is that necessary?

It's stamped 308 so I don't see why I should use military over commercial brass.

I understand the point of the small base die is to make it a little smaller. If a regular die works fine should you get the x die?

I have no dies yet.

As always, thanks in advance.

[Finarfin]

I'll be using cci #34 primers. Any other tips are welcome.

[Gunor]

Search for:

Go read BruceB's thread on the M-1A and 308.

Larry Gibson and X dies.

And likely no need for small base dies.

Buy box of Sierra 168 HPBT bullets and load 41 (or so) grains of 4895 - then you can determine the accuracy potential of your rifle. My opinion - if a M-1A doesn't shoot that load well... - it is kind of a 'gold standard' for me.

+1 on cci #34 primers

Geoff in Oregon

[RG1911]

For what it's worth, before back surgery I used my M1A for NRA Highpower competition. I used Lake City Match brass, Winchester Large Rifle primers, 155-, 168-, and 178-grain bullets (depending on the distance), and surplus IMR4895 powder. For the 600-yard portion, I used commercial Lapua brass.

A couple thousand loaded using regular RCBS dies and not one feeding or chambering problem (or slam fire from the "soft" primers).

Just FYI, I also don't use small-base dies in any of my AR-15s or AR-10s. Absolutely no problems.

As always, YMMV.

Have fun with a great new rifle,
Richard

[Larry Gibson]

If you want long brass life (20+ firings per case instead of 3 - 5) and don't want to have an incipient head separation leaving the front part of the case in the chamber use the RCBS X-die. You do not need nor want the SB of "AR" X-dies. The regular .308W X-die set is the one to get.

Larry Gibson

[Finarfin]

If you want long brass life (20+ firings per case instead of 3 - 5) and don't want to have an incipient head separation leaving the front part of the case in the chamber use the RCBS X-die. You do not need nor want the SB of "AR" X-dies. The regular .308W X-die set is the one to get.

Larry Gibson

I do like longer case life! Do they last that long with full power loads as well or just lower cast loads?

Are there disadvantages to the x die? I read that they are much harder to work the lever on and that you can't use spray lube. I am fond of hornady one shot.

If there's only upside I can't see any reason not to get these over a different variety.

[Finarfin]

Search for:

Go read BruceB's thread on the M-1A and 308.

Larry Gibson and X dies.

And likely no need for small base dies.

Buy box of Sierra 168 HPBT bullets and load 41 (or so) grains of 4895 - then you can determine the accuracy potential of your rifle. My opinion - if a M-1A doesn't shoot that load well... - it is kind of a 'gold standard' for me.

+1 on cci #34 primers

Geoff in Oregon

I've read the sticky about Bruce's cast loads in the m1a. Will look for the other.

I have been planning on using this h4895 I picked up. Do you think that works as well? I got it because it seems so versatile, it works in many loads, cast and jacketed, and can be reduced for plinking loads.

I was thinking about primarily using Speer 165 grain soft point boat tail, but will give it a go with those to see what she does. They recommend against soft points so I will try it and see if I have any problems, supposedly it can shave off the tips and gum up the works.

[country gent]

Both my M1As are krieger barrels with match chambers and throats ( short throated so 155 sierras touched rifling at mag length) I use standard dies and load IMR 4895 for years with 155s and 168s. The 1 thing to watch for and check is to make sure you push the shoulder back .002-.003 from fired dimension. This will extend case life and help with chambering.

[Finarfin]

Ok, well I have two st00pid questions.

1. How do you measure the shoulder? Just from the base to the point where it begins?

2. How do you measure headspace? I've never understood this. Mine came with a slip that says what it was measured at.

[country gent]

Sinclairs hornady make an attachment to measure this with calipers. The measure ment you want is from case head to datum on shoulder. I made a little gage for this from round stock fired neck dia +.005 and the shoulder cut in one face its 1" long. While not an actual measurementor dimension it is comparative from fired to sized cases. Sometimes sizing a case will move the shoulder forward if not pushed back correctly. Another that can cause this is a tight un lubed expander ball pulling the shoulder forward slightly when coming out.

[376Steyr]

Head on over to M14Forum.com and their "Ammunition" sub-forum. There is a wealth of information there. First thing to learn is the M1A is a different animal from a bolt action, and trying to load for it like it was a Winchester Model 70 will get you in trouble.

[Finarfin]

I don't have a bolt action, so no bad habits to break! I'll take a gander at it, thanks for the idea.

[Bill*B]

Military brass has a thicker case head than commercial - if you are pushing the envelope and loading 50K + psi ammo, it makes a head separation less likely. If you are loading 20 - 25K psi cast bullet loads, I doubt that it matters.

Of course the case capacity of the two is different - military brass (because of the thicker case head) has a smaller internal volume, and loads will need to be reduced if you are using data for commercial brass.

[Wayne S]

IF you can visualize what happens to a case when it is FL resized , you will understand how an X die extends case life so much. The only inconvenience in using an X die is the trimming all cases to a uniform length.
If RCBS would incorporate a neck collet for sizing the neck and eliminate the expander ball that would help case life ever more.
+ 1 for using a match bullet to set the accuracy standard for your rifle. I used a 175 SMK to set the standard and used it as a comparison against pulled 175's and cast bullets.

[madsenshooter]

No small base dies are necessary. In fact, when I had an M1A a couple fellows told me I should get Lee dies, because they size less. They were brothers, one a Columbus cop, the other a state Trooper who was called for sniper duty whenever the residents of the Ohio prison systems got rowdy. Both were Vietnam vets and loved their M1As. Wish they'd have told me mine was a Devine made rifle, I'd still have it!

[badgerblaster]

I got my NIB M1A Loaded last spring and immediately bought rcbs regular dies (green box). Rounds would not eject. Had to use a rubber mallet to eject brass. Did some research and bought rcbs small base dies (black box) and have not had a problem since.

That's just my personal experience with my M1A. The other thing I found out is that it is a lot of fun to shoot!

[Larry Gibson]

RCBS X-DIES: A TEST

By Larry M. Gibson

Surprisingly, there was little fanfare with the introductionof RCBS’s X-Dies.All I saw were smallblurbs in the trade magazines and mention of them in Rick Jamison’s Shooting Times column.Advertised to reduce or eliminate casestretch the question is; do they?Myreal interest was: Will they reduce case stretch, i.e. increase case life, of7.62 NATO (that’s .308 WIN to you non-mil types) cases fired in M14/M1A’s?

The number of reloadings per case for M14/M1A’s is probablythe worst of any rifle/cartridge combination short of the .303 Lee Enfieldfamily.Incipient head separation is thereason for case loss.My experience withrack grade M14/M1A’s is five good firings per case with the sixth being a“throwaway”. This is only if the brass was fired in a bolt gun or M14/M1A tobegin with. A match M14/M1A with a tight “match” chamber may get 1-2 morefirings but more often not. If surplus once fired brass is used the firstfiring was more than likely done in a machine gun and only 1-2reloadings/firings are possible before head separation.

Most head separations can be identified as a speckled crackforming around the case just ahead of the web at the expansion ring.This crack is sometimes quite obvious.Then on some cases the head will separatefrom the case on ejection.Many timesboth parts of the separated case are ejected.But sometimes only the head is ejected leaving the front half of thecase in the chamber.The rifle picks upthe next round attempting to chamber it and things get jammed up. Notgood!The other question here; is theregas cutting damage to the chamber?

What causes this incipient headseparation to happen?Simply put, onfiring, the case expands to grip the chamber walls sealing off the gaspressure.When the bullet leaves thebarrel pressures are reduced and the case contracts (not to its originaldimensions) releasing it’s grip on the chamber walls and allowing extraction.However, it appears that the M14/M1A begins extraction prior to the pressuredropping completely.The cases do notcontract as much as they would if fired in a bolt action for instance.Compounding the problem is the mil-specs formilitary chambers are somewhat generous in their diameter dimension to allowfor functional reliability during combat conditions.When full-length resizing (necessary forM14/M1A) case walls are squeezed in first.This pushes the shoulder forward.The shoulder is then set back by the FL die and the brass flows forwardinto and elongating the neck.Thisincreases the case length on each resizing considerably.Also, since the brass at the expansion ringexpanded and was squeezed in and forward during resizing the case getsprogressively thinner in that specific area.The result is, eventually, a head separation at that thinning location.Most mil-spec (US)chambers allow for a maximum case length of about 2.045”.I, like most M14/M1A users, have foundtrimming unnecessary. Incipient case head separation will occur, and casesdiscarded, before maximum case length is reached and trimming is necessary.

Are these RCBS X-Dies a cure forthis? I decided to use my rack grade M1A to put them to the test. The issue GIbarrel has quite a generous mil-spec chamber with headspace being within tolerance.This usually results in the fifth firingbeing the “throwaway” for brass in this rifle.It has untold thousands of rounds through it, many rapid fire.Accuracy capability is 2 1/2-3 MOA with M118Special Ball or equivalent reload. This would be the best “worst case” testrifle. All rounds would be fired with the rifle loading from the magazine innormal semi-auto function.Slow firesingle loading technique would not be used.

For ammunition I selected 10rounds of LC 92 M118 Special Ball.A checkfor concentricity revealed a runout of .011” for one round with the othersbeing .004-.007”.

My M118 equivalent load is:

BRASS: The 10 LC 92 cases from theselected M118 Special Ball
PRIMER: Winchester WLR
POWDWER:H4895 – 41gr
BULLET:M118 174gr
CARTRIDGE OAL: 2.8”

Other than deburring the flashhole, chamfering the case mouth and removing the primer pocket crimp, there wasno special “case preparation” done. Cases were measured after each resizingwith the minimum to maximum case lengths recorded.Concentricity was checked after eachloading.Two cases (marked and tracked)consistently had .004-.005” runout with all others being .0005-.003” throughoutthe test. Neck thickness (outside diameter) was measured after each loading tocheck for brass flow into the neck area.

The test would be concluded basedon any one of these criteria:

Any sign of incipient headseparation.
Case buckled or dimensionallydamaged/deformed during resizing.
Split neck or body.
Case length exceeding 2.045”.
Loose primer pockets.
Neck thickening to cause excessiverunout (.010”).
Drastic deterioration of accuracy.(6^th, 12^th and 18^th groups will
be fired in Fulton Armory Match M1A to verify accuracy)
Malfunctions caused by damaged(dinged up) cases.

All test firing was conducted atTacoma Rifle and Revolver range.
The range has solid cementbenches, which were used with sandbag rests front and rear.A 100 yard reduced “A” bull target wasused.All targets were at 100 yards.I set up the Oehler 35P to chronograph allrounds fired for each 10 shot string.But as the test went on, and on, and on I quit chronographing after the10^th string. Chronograph results were consistent and showed novariation other than that normally expected.The LC 92 M118 averaged 2600 FPS and the M118 equivalent reload averaged2575 FPS for the subsequent 9 ten shot strings chronographed.

The RCBS X-Die was installed in myPacific single stage press and adjusted as per the instructions.It’s really quite easy.These dies differ from other FL dies in thedimension and design of the decapping rod.The diameter of the rod is larger and appears to act as a mandrill ofsorts.There is a shoulder on it, whichcontrols the length as the case. Apparently the case is prevented fromstretching by the case mouth butting against this shoulder. Thus the decappingrod must be carefully adjusted as per the instructions.This shoulder is the key to the success ofthe die.

I found on the second resizingthat the expander was really getting hard to pull through the necks.Also, the lengths of the cases were varyingmore than I thought they should.Caselubing technique was changed to standing the cases in a tray. They were thensprayed lightly with Dillon case lube. With this method the necks (lube getssprayed lightly into the case mouth) pulled over the expander quite easily andthe uniformity of case length dramatically improved. Cases are cleaned again toremove the lube.This should also removethe lube from the inside of the case neck.

Throughout the test case lengthnever exceeded 2.027” and actually remained quite consistent.After the 12^th resizing the neckshad begun to thicken by about .001” at the shoulder to taper forward about 1/3of the way to the case mouth.However,this did not adversely affect concentricity or accuracy.

The case rims got a little beat upbut there were no malfunctions of any kind.This included the 2 firings in the match chamber M1A.Primer pockets remained tight throughout thetest.I thought the case mouths wouldrequire rechamfering but they did not.Accuracy remained consistent with the rack grade M1A.The LC 92 M118 ten shot group was 2.8”.The last (15^th) ten shot groupwith the M118 equivalent load was 2.4”, the average of groups 2-15 being2.7”.Groups 6 and 12 were fired withthe match M1A to verify the accuracy and both were 1.6”.

[Larry Gibson]

The test was concluded after the15^th firing based on incipient head separation.One case developed that slight speckledcircle at the expansion ring.There wasno clear-cut crack and probably no gas cutting happened.I may or may not continue the test with therest of the cases.

Tabulated below are themeasurements after each resizing:

RESIZING---MINIMUM----MAXIMUM---INCREASE
------------CASE--------CASE-----INCASE
------------LENGTH-----LENGTH----LENGTH

1-----------2.013------2.019----------

2-----------2.021------2.025------.006

3-----------2.025------2.027------.002

4-----------2.025------2.027------.000

5-----------2.022------2.027------.000

6-----------2.023------2.025----(-).002

7-----------2.023------2.025------.000

8-----------2.024------2.026------.001

9-----------2.024------2.027------.001

10----------2.025------2.027------.000

11----------2.025------2.027------.000

12----------2.024------2.026----(-).001

13----------2.025------2.026------.000

14----------2.024------2.027------.001


Case length evened out at thethird resizing and remained fairly consistent.Interestingly #’s 6 & 12 that were fired in the match M1A show adecrease in length!At #12 is where Idetected a thickening (.001”) of the case necks in the shoulder area whichtapered forward.Again this did not affectconcentricity or accuracy.


Questions not addressed in thistest:

1. Case life when used in matchchambers or bolt guns?

2. Case life of cases alreadyfired several times?

3. Case life of surplus once-fired(in machine guns) cases?

4. Case life of civilianmanufactured (Rem,Win,Fed,PMC,et all) cases?

The answers to these questionswill probably have results as positive, if not more so, than this test.

My technique for loading M14/M1Aammo now will probably be as follows:

1. Clean cases
2. Stand cases in loading traysand spray lightly with Dillon case lube.
3. Size with RCBS X-Die usingPacific single stage press.
4. Clean cases.Clean primer pockets. (On 1^stresizing prep cases by: remove primer crimp, deburr flash hole, turn necks,trim to uniform length and chamfer case mouth). Conduct visual inspection fordefects (split necks, head separation, etc.).
5. Load on Dillon 550B.Use a Bonanza neck size die or a Redding bushing die atstation 1.This may or may not benecessary.The idea here is to iron outany dents the second cleaning may have caused in the case mouth and maybeuniform neck tension on the bullet.

This limited test revealed that;using the RCBS X-Dies, when reloading for the M14/M1A, one may expect 3 timesor more firings per case as when using standard dies. I have been using BonanzaBenchrest FL Dies prior to this.I’ve neverfound the need for small base dies, as some recommend, for they really shortencase life.

This increase of case life is, inmyopinion, truly astounding. Also, it appears casetrimming is unnecessary. I would hope RCBS would make them in a widerarray of caliber’s than currently available.I will buy more of them.When Ithink of the thousands of 5-6 times fired brass I have thrown out … Oh well!

Good luck, good shooting and goodhunting

Addendum: I continued on with thetest using the remaining nine cases.Onthe 16^th firing another case showed signs of incipient
Casehead separation.The other eight caseshave been fired 20 times.I doubt I’llcontinue on as 20 firings per case is enough.

[ShooterAZ]

I concur on the case longevity using the RCBS X-Die. I'd be lucky to get 20 firings though, as my M1A is very hard on case rims. They get pretty banged up at around 10 or so.

[M-Tecs]

Looks like I will be purchasing some X Dies!!!!!!!