Looking for a plain base M1 Garand bullet mold

[Dimner]

Howdy gents. Summer is coming faster than ever, and that means CMP high-power style shooting at my local club. This year I plan on using 2 rifles off and on each week. An AR-15 with cast, if I get that project finished and also an M1 Garand.

I have plenty of gas check molds that should work just fine with the Garand, but no plain base molds that are heavy enough to cycle the action.

So here's what im looking for. A plain based bullet that either with or without PC that is 2 moa at 100 yards, velocity is negotiable, but if I understand my research it will have to be over 1800fps probably more since this is a plain base and has less start pressure.

So, anyone have any suggestions on what molds to look at first?

 

[MW65]

There's been a few threads on cast in the Garand. I'm playing around with a NOE 314299, sized to .311. My current plan with the match loads is to use 4895, with g/c'd 314299's.... i don't PC, so that's what i'm planning on. We shoot at 200yds for service rifle, and there's also a silhouette match with targets up to 200yds.

Garands are a finicky critter.... lots can affect accuracy... trigger latch pressure in the stock, fore end looseness, how the gas cylinder sits, how tight the sights are, the crown, etc.

A good starting point is to see how accurate it is with good handload jacketed ammo. Set your expectation to that size group with cast.

Since i don't PC, i keep my plain base stuff below 1400fps...

good luck!!!
-Andy

 

[fiver]

it ain't the bullet's fault that the gun don't cycle.

 

[Dimner]

yeah, my plan is to work with jacketed first, and then gas checked 311291... but I also want to develop a plain based bullet load. That will keep me shooting longer. I only have about 500 gas checks, and 30 cals have been out everywhere for a while.

 

[Joshua]

5/16” = .3125”
You can make any 30cal mold into a plain base with a 5/16” drill bit, and a drill press. Do you have a Lee mold kicking around that you want to modify? Maybe the 309-200, or the 312-155?

 

[fiver]

just get Tom to cut you a plain base 311291.

 

[Dimner]

Here are three off the shelf profiles that I was considering from NOE.

 

[MW65]

Here are three off the shelf profiles that I was considering from NOE.

...

There's a bit of concensus that the heavyweight cast tends to work the action better... To maintain the port pressure at a reasonable level. For me & my rifle, I'm sticking with rcbs 30-180-fn & noe 314299... I'd read up on the cmp forums and also check out bob s garand load. Hope that helps!

 

[Winelover]

Unless your willing to give up the autoloading feature.................your gonna need a GC or cast your bullets extremely hard. At least that's been my experience with my AR-10. Slower powders are more apt to cycle the action. Forget powders like SR 4759 or AA 5744...................go slower.

 

[Ian]

Listen to Fiver and Winelover.

The receiver shape is designed to feed one nose length and one nose profile. Get it wrong and things bind horizontally and jam. The function is also based around a standard load producing a certain peak chamber pressure, port pressure and pressure curve with a certain weights bullet. You can shift things around considerably and still have function but there are limits. I don't think plain-based bullets are within acceptable limits of function and accuracy, but I do encourage you to try powder coating and see if something can be worked out. Try powders in the 4064 to 4350 range (any slower won't reduce enough safely).

 

[Joshua]

But yes cast works very well in the garand. The Lee 200gr works well.

Normally use a 31-142C (145gr) PB for the BO @ 2100 fps.

I’ve just read that you need 1900fps with a 200gr bullet, using 4895 or slower to cycle a Garand, with a standard gas block.

I’ve also read that quite a few of you are running lighter PB PC 30cal bullets in 300 BO at speeds up to 2100fps with much faster powders than we are talking about with the Garand.

So what am I missing? Why is it that cast PB PC bullets works just fine in a 30cal AR at 2100fps.

I don't think plain-based bullets are within acceptable limits of function and accuracy,

But they won’t perform in the Garand platform with gentle, slower powders, going slower?

I do acknowledge that the Lee 200 is a bore rider and could very well loose accuracy once pushed over 1800fps. But there has to be a bullet shape that will be accurate. The PC we know can withstand the velocity.

 

[Dimner]

Well. Why reinvent the wheel eh? At least at first. Good advice from all of ya. Rather than buy a new plain based mold, I noticed that sages has his brand of 30 cal checks in stock. So I bought 4k of them. So we will see how those work vs gator checks. I can't imagine I'll be disappointed

Still want to try a plainbase project in a while. I have an 8lb jug of ramshot hunter that seems to be the right powder for the job.

 

[Dimner]

I’ve just read that you need 1900fps with a 200gr bullet, using 4895 or slower to cycle a Garand, with a standard gas block.

I’ve also read that quite a few of you are running lighter PB PC 30cal bullets in 300 BO at speeds up to 2100fps with much faster powders than we are talking about with the Garand.

So what am I missing? Why is it that cast PB PC bullets works just fine in a 30cal AR at 2100fps.




But they won’t perform in the Garand platform with gentle, slower powders, going slower?

I do acknowledge that the Lee 200 is a bore rider and could very well loose accuracy once pushed over 1800fps. But there has to be a bullet shape that will be accurate. The PC we know can withstand the velocity.

I think it has to do with the differences in the gas systems. The gas port in most 300BO is at pistol length, so you get that pressure back to the bolt very quickly with very little distance traveled. That means fast powders work well with that gas system as the pressure curve with fast powders is a big initial spike that quickly subsides.

With a garand gas system, you need a pressure curve that stays near max pressure a longer time because of the longer gas system. So slower powders will take longer to get to max pressure but also keep up the pressure longer.

 

[Joshua]

I think it has to do with the differences in the gas systems. The gas port in most 300BO is at pistol length, so you get that pressure back to the bolt very quickly with very little distance traveled. That means fast powders work well with that gas system as the pressure curve with fast powders is a big initial spike that quickly subsides.

With a garand gas system, you need a pressure curve that stays near max pressure a longer time because of the longer gas system. So slower powders will take longer to get to max pressure but also keep up the pressure longer.

View attachment 20294

I understand the difference in the gas systems. Why slower powders are needed in the Garand. That wasn’t my question. My question had to do with the durability of the powder coating on plain based 30cal bullets pushed to 1900-2100fps. Why that works fine in one situation but not in another?

The only reason I mentioned the powders used in the two very different systems is that the faster more violent burns of powder like H-110 should in theory affect the base of a PC bullet more aggressively then the slower powders. The slower powders should actually make it easier to achieve the velocity and pressures required to cycle the action of the Garand, and not damage the base of the bullet.

I acknowledge that the case volumes are so completely different between these two cartridges. That in the case of the 30-06 fillers maybe required to make a plain based bullet accurate. I personally am uncomfortable with the use of Dacron fillers because when used incorrectly chamber ringing can happen. To maintain accuracy with heavy bullets and lower charges of slower powder, a filler may need to be used, to attain accurate loads in the 2000fps/proper pressure range.

I guess my real question is at what velocity will a properly shaped 30cal powder coated, plain based, bullet loose it’s ability to prevent leading and accuracy is lost. I was under the assumption that 1900-2100fps was within that range, or is that only possible with Popper’s copper infused alloy, or possibly an alloy like Lyman #2, that this is possible?

And not to muddy the waters but isn’t this also where the use of an adjustable gas block can help the shooter develop an accurate load that will also cycle and not damage the op rod?

 

[Ian]

I don't know about decent accuracy with PB PC cast bullets at 2000 fps. Maybe Popper is getting that? You're going to need close to that velocity with 200 grains to make enough gas volume and pressure at the port to cycle an M1. So it's right on the razor's edge of too little gas and too much speed for accuracy with the bullet. Most people have enough trouble getting 2 MOA out of an M1 using gas checks.

 

[popper]

Reports are that fast powders will bend the cycling rod - whatever you call it. I did get decent results (MOA) with PB in the BO carbine gas, 2100 fps. I shot that bullet from 308MX fast and got good results too but didn't crony. It's a light version PB of the 31-165C. Ian & I run our ar10 30cals fast, no problem but they are DI guns, not op rod. BruceB has a good writeup for cast M1 on the 'other site'.

 

[Ian]

Bruce wrote about the M1A, different beast. Slow powders that increase muzzle pressure too much is what bends the op rods, but only if you load them to full chamber pressure. Reduced loads of slow powder that equal full charges of 4895 at the gas port are perfectly safe provided the usual reduced load precautions are observed.

 

[462]

Most people have enough trouble getting 2 MOA out of an M1 using gas checks.

Thread drift alert!
Not out of the realm of reality that many people have enough trouble getting 2 MOA out of an M1 using jacketed bullets.

 

[fiver]

well yeah,,, they weren't really designed nor built as target rifles.
2-3-4 inches at 100 is good enough to fling lead across the street or an open beach when 300 other guy's are doing it too.

 

[quicksylver]

I have had good results with the lee 160 grain mold in my M1,, but its looseand will function with a lesser charge of powder than most, I have also found that opening up the clips 'spreading them" helps ALOT!, Accuracy only suffers because getting the action to functions puts the velocity over what a cast can handle in a 10 twist, so your ar 10 with a 12 twist has a huge advantage in that regard, rebarrel with a 12 twist might show a marked inprovement, Dan