Crimp/No-Crimp Garand Ammo

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D.B. Cooper

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To crimp or not to crimp.

I'm a bout to start loading up a few different loads for my M1 Garand for service rifle. We had a discussion about this several months ago, but this was one thing that didn't come up.

I'll be loading 150 grn and 168 grn projectiles to be loaded single shot from an open bolt. (200 and 600 yrds respectively.) And 150 grn projectiles for the 300 yrd rapid fire strings.

My thought is I'll get better accuracy from an uncrimped cartridge. However, do I need to crimp to make sure the cartridges are reliable and don't come part under recoil? Should I be crimping everything, or just the ones I load into en block clips for the rapid fire?
 
I crimp all my Garand ammo (and other rifle ammo) with Lee collet crimp dies. I even use the Lee collet crimp on the ammo for my bolt action target ammo.
 
I don’t crimp and most people I’ve talked to who load a lot for the Garand don’t crimp. I also ignore any cannelure and load about as long as will fit in the magazine and feed properly without touching the lands, usually around 3.30” or just shy.

If crimping makes you feel better, go ahead.
Try some with and some without and see which shoot better for you.
 
Then you’re golden. Ah, it should go without saying that you are full length resizing every time. I’m saying this for anyone who might browse up this thread in the future.
 
Uniform primer pocket depth, seat primers below case head, and bump shoulders back .004-.006 thousands. Your expander should be at least .002 smaller than bullet dia. No crimp needed. A 4895 powder is best
 
I'm exactly the the opposite. I prefer not to crimp.
Knowing how much neck tension and how much contact neck to bearing surface will be a good guide. If you have almost full neck to bearing surface contact and at or greater than .002 neck tension I would not be very concerned. If your seating as long as possible and have no idea what your neck tension is, then you may want to do some testing on the uncrimped to see if you get any bullet movement.
 
There is absolutely no need to crimp bullets in a Garand. There are 30-06 targets below and 308 Win targets, shot in competition out of my match Garands Use a sizing die that provides good neck tension and seat your bullet. Crimping will damage a match bullet by squeezing it in the middle, not that the affects are easy to see, but I don't understand paying good money for the best bullets in the world, only to move the center of gravity from the axis of rotation with a crimp die.

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For all my gas guns, the Garand included, I crimp my blasting ammo, but I don't crimp target ammo. I do use a taper crimp die, as opposed to a roll crimp... all I'm trying to do is prevent bullet setback from recoil, not 20 year deep storage under water. As Slam suggests... why pay all that money for a consistent bullet, then mash it with a crimp die?
 
Another vote for no crimp. A pass with the LFC likely won't hurt, but IMHO is not necessary. I shoot the Garand in the same application as you, although mine is mostly run on the 200 yard JCG course, I do occasionally take it out for OTC. I prefer one load for all with a 168 BTHP and 46.0 IMR4064, never crimped. You might get some savings in cost and recoil by using a 150 FMJ for RF, but I think any advantage real or imagined would be negated by fiddling with the zero shift and the general Pain of switching loads mid-match.
 
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When I got my Garand, I did a lot of research on crimping, and being a "show me" kinda guy, I experimented for myself. I started by crimping, lightly, all my handloads (mostly HXP brass with Hornady bullets), with the stock seating/crimping die. I'd shoot about 6 out of a clip, and removed the 7th from the chamber and measured OAL. No movement. Next batch tried a Lee collet crimp, tested several and got same results. Next batch was no crimp, just F/L sized and seated. Fired 6 of a clip, removed 7th and 8th and measured OAL. No bullet movement. Now this was in my gun, with new Criterion barrel, using my dies, my Hornady bullets in my once fired HXP brass...
 
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For what’s worth, I shoot s bolt gun based on a Remington 700 action fed from a box magazine. I’m not ginger with it either, when I’m taking advantage of a favorable wind state. I’ve never crimped. My chamber is so tight that I just use a full length sizing die to get the neck. Neck tension has always been enough.
 
There is absolutely no need to crimp bullets in a Garand. There are 30-06 targets below and 308 Win targets, shot in competition out of my match Garands Use a sizing die that provides good neck tension and seat your bullet. Crimping will damage a match bullet by squeezing it in the middle, not that the affects are easy to see, but I don't understand paying good money for the best bullets in the world, only to move the center of gravity from the axis of rotation with a crimp die.

Those were some pretty darn good targets. Out of curiosity, did you have yours bedded and "accurized" or did you keep it "as issued" for JCG matches?
 
When you guys say "set the shoulder back" how are you doing that and how are you measuring it?

As I understand it, you're pushing the shoulder (the bottle neck part) back toward the base of the case, I assume to account for forward case expansion. Is this to ensure the cartridge seats fully into the chamber, so as to avoid a slam fire, or is there some other reason/benefit for doing it?
 
That’s the reason. I only measure by sizing to the lower step of a Wilson case headspace gauge. There are more accurate methods but they’re a bit of a hassle.
 
That’s the reason. I only measure by sizing to the lower step of a Wilson case headspace gauge. There are more accurate methods but they’re a bit of a hassle.
Amazing how much we didn't know before the internet. Last time I loaded for this gun , I used a Lyman reloading manual for 30-06. Near full case (near max charger) of 4064 with a 168 grn bullet seated to just off the lands. Never heard of slamfires or bent op rods. lol
 
Those were some pretty darn good targets. Out of curiosity, did you have yours bedded and "accurized" or did you keep it "as issued" for JCG matches?

My match 30-06 is this rifle:

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Rear lugged receiver, bedded, Barnett barrel, all the standard modifications of the era. A professional did the work on this rifle. I don't have a picture of my 308 Win, Barnett did install one of his barrels but I did the stock work. It is absolutely not legal for JG matches.

If a rack grade Garand will hold the black, that is all the thing was expected to do.

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Local 200 yard Garand match with rack grade Garand, prone with sling. This is an above average rifle and all it will do is hold the black. Sometimes, not even that.

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different rack grade rifles, prone with sling at 100 yards. The issue Garand was not a target rifle nor was it expected to be.

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When you guys say "set the shoulder back" how are you doing that and how are you measuring it?

As I understand it, you're pushing the shoulder (the bottle neck part) back toward the base of the case, I assume to account for forward case expansion. Is this to ensure the cartridge seats fully into the chamber, so as to avoid a slam fire, or is there some other reason/benefit for doing it?

All gas guns unlock before pressure is zero, in an attempt to length the duration of the gas impulse and to use the residual pressure to blow the case out of the chamber.

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These cases were lubricated with paste wax and fired out of a match M1a

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The shoulder has clearly moved forward as the case was extracted. If I did not lubricate the cases, I would have also experienced case head separations such as these cases:

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I recently purchased this gauge, it measures width as well as length. It is cut with a SAAMI reamer. If you don't know the headspace of your rifle chamber, just size to gauge minimum.


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If a rack grade Garand will hold the black, that is all the thing was expected to do. The issue Garand was not a target rifle nor was it expected to be.

Yeah, I've read and/or heard that the Army considered 4 MOA acceptable when they adopted the M1. If true, that would explain why I'm the only one on the line with an M1, and everyone else is shooting an AR.

I recently purchased this gauge, it measures width as well as length. It is cut with a SAAMI reamer. If you don't know the headspace of your rifle chamber, just size to gauge minimum.

So...you're using the sammi go/no-go gauge to measure your shoulder set back? What are you doing on your sizing die to accomplish that? Seems to me that the die is going to size the brass to whatever shape and set back it was machined to; it doesn't seems like that is user adjustable. If I turn down the adjustment on the die, all it's going to do is seat the projectile deeper in the case. I must be missing something.
 
Slamfire is a wealth of knowledge but one you get him talking about slam fires and lubricated cases you’re going down a rabbit hole from whence you may never return...

:rofl:

There is more to properly setting your size die for a particular rifle than just dropping the case into a go/no go gauge, but unless you just have to have the 'inth degree of accuracy, I wouldn't bother. A rack grade Garand is not one that would benefit from it, either, I'd just FL size my brass and go with it... because that's what I do.
 
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