M-1 Garand Loads

[Bill2311]

#1 for the tried and true IMR4895. I hear many different theories and experiences on different powders, but I decided to stay with what works.

[John Kepler]

Casual targets may not require the competition shooter demand, but golf balls at 30 yds are kinda a challenge........

You think? Let's put this little factoid into perspective. A golf ball at 30 yds, regulated for a .30 cal bullet (1.680" for a PGA regulation golf ball + 0.616" for the bullet) is a 7.6 MOA target! Meaning that a hit on your "challenging" golf ball target would buy you a 7 on a standard 200 yd. SR Highpower target, and 7's won't buy you squat in Highpower!

Ain't math a b!tch!

[Bayou]

Can we get back to the OP question please as I'm interested in the same subject. I understand all the physics about burn rates and charge masses and their time dependent effect on bore pressure. BUT nobody made any comments on how things may or may not be OK with H4350 IF an adjustable gas plug is being used.

For purely economic reasons I would like to be able to reload for the M1 Garand using H4350. I have about 7-1/2 lbs of H4350 on hand and I don't use this powder too much. I got it for a 270 hunting rifle I have but I just don't do that much hunting. I also have been using it for a Yugo M48 Mauser, but again I don't shoot that rifle a whole lot either. I also have IMR4064 and AA250 and I know they are better powders for the M1G but I use these powders a lot for 308 and 223.

It looks like a min charge of 55 gr of H4350 would provide an acceptable bullet velocity. Assuming you can vent the excessive port pressure with the adjustable gas plug and not damage the rifle's cycling mechanism, would it be ok to go this route? Are there any other considerations like stronger blow back, would the bolt take more abuse with H4350?

Thanks!

[John Kepler]

It looks like a min charge of 55 gr of H4350 would provide an acceptable bullet velocity. Assuming you can vent the excessive port pressure with the adjustable gas plug and not damage the rifle's cycling mechanism, would it be ok to go this route? Are there any other considerations like stronger blow back, would the bolt take more abuse with H4350?

Thanks!

With all the appropriate caveats, yes, with a properly configured McCann device or something equivalent, you can safely load H4350 for a Garand without any significant problems. Hell, I've been shooting Vihtavuori N560 (LOTS of it too!) with a 190 gr SMK on top, essentially a very hefty bolt-gun load, in my similarly configured Long Range Garand for years!

The only thing of note is that the slower powders seem to induce a longer duration recoil (could be my heavy bullets too!) that is hard on the stock-bedding. I have to skim-bed my competition LR Garand about every 500 rds., so you might find your "issue" Garand getting loose in the stock sooner than you'd expect. I think that's a very distant possibility if you keep your bullet weights more toward the 150-168 range, but had to give you everything I've noted over the years.

[Parashooter]

It looks like a min charge of 55 gr of H4350 would provide an acceptable bullet velocity. Assuming you can vent the excessive port pressure with the adjustable gas plug and not damage the rifle's cycling mechanism, would it be ok to go this route?

If you're talking about 150-grain bullets, the first part of the answer is that we can expect about 8% higher port pressure compared to a load of 4895 giving the same velocity. (This QuickLoad output graph models 4895 vs H4350 for a velocity of 2800 fps. Cutting the H4350 charge to 55 grains lowers the velocity by some 30 fps and has no significant effect on the pressures.)



Presuming the modeling is accurate, we see how the slower powder gives slightly less peak pressure but also higher pressure farther down the barrel (mostly because the heavier charge produces more gas). At the gas port, the difference is about 1000 psi (8.3%). If we assume this load of 4895 would give the kind of port pressure for which the M1 was designed, it's probable the H4350 load would give enough additional speed to the operating rod to cause eventual damage.

The second part of the answer is that an adjustable gas plug, properly designed and adjusted, will easily bleed off the excess pressure from the gas cylinder. That's why they make them!

Finally, the added mass of the heavier charge adds slightly to the rifle's recoil energy. In theory, this will hasten whatever wear occurs during "normal" recoil. In practice, you would wear out several barrels before observing any difference from this effect.

An alternative to installing the adjustable plug is to employ heavier bullets for which a smaller charge of the slow powder would be appropriate -



Here we see a model (which really means "educated guess") of the same 150-grain 4895 load compared with a 200-grain bullet ahead of 51 grains of 4350. Peak pressure is higher, velocity lower, and the port pressure is virtually identical. The main reason is that the two charges are very similar in mass and consequently produce about the same quantity of gas. Thanks to the greater mass of the 200-grain bullet, recoil energy will be significantly higher than with the 150's - something both your shoulder and your rifle's bedding will notice.

[Bayou]

With all the appropriate caveats, yes, with a properly configured McCann device or something equivalent, you can safely load H4350 for a Garand without any significant problems. Hell, I've been shooting Vihtavuori N560 (LOTS of it too!) with a 190 gr SMK on top, essentially a very hefty bolt-gun load, in my similarly configured Long Range Garand for years!

The only thing of note is that the slower powders seem to induce a longer duration recoil (could be my heavy bullets too!) that is hard on the stock-bedding. I have to skim-bed my competition LR Garand about every 500 rds., so you might find your "issue" Garand getting loose in the stock sooner than you'd expect. I think that's a very distant possibility if you keep your bullet weights more toward the 150-168 range, but had to give you everything I've noted over the years.

Cool, and thanks for the reply. My 30-06 dies and schuster adjustable gas plug should arrive tomorrow. I'm going to give H4350 a try and see what happens.

[Bayou]

If you're talking about 150-grain bullets, the first part of the answer is that we can expect about 8% higher port pressure compared to a load of 4895 giving the same velocity. (This QuickLoad output graph models 4895 vs H4350 for a velocity of 2800 fps. Cutting the H4350 charge to 55 grains lowers the velocity by some 30 fps and has no significant effect on the pressures.)



Presuming the modeling is accurate, we see how the slower powder gives slightly less peak pressure but also higher pressure farther down the barrel (mostly because the heavier charge produces more gas). At the gas port, the difference is about 1000 psi (8.3%). If we assume this load of 4895 would give the kind of port pressure for which the M1 was designed, it's probable the H4350 load would give enough additional speed to the operating rod to cause eventual damage.

The second part of the answer is that an adjustable gas plug, properly designed and adjusted, will easily bleed off the excess pressure from the gas cylinder. That's why they make them!

Finally, the added mass of the heavier charge adds slightly to the rifle's recoil energy. In theory, this will hasten whatever wear occurs during "normal" recoil. In practice, you would wear out several barrels before observing any difference from this effect.

An alternative to installing the adjustable plug is to employ heavier bullets for which a smaller charge of the slow powder would be appropriate -



Here we see a model (which really means "educated guess") of the same 150-grain 4895 load compared with a 200-grain bullet ahead of 51 grains of 4350. Peak pressure is higher, velocity lower, and the port pressure is virtually identical. The main reason is that the two charges are very similar in mass and consequently produce about the same quantity of gas. Thanks to the greater mass of the 200-grain bullet, recoil energy will be significantly higher than with the 150's - something both your shoulder and your rifle's bedding will notice.

Parashooter,

Thanks for the reply and the work required to run these simulations. I do appreciate the effort required to do this. One thing I learned on one of my reloading sites is that it's a bad idea to use less than the minimum published charge of a slow powder. So I would never try a H4350 charge below 55 grains. I'm going to start out with 55 gr of H4350 and an adjustable plug and see if I can make it work. If it doesn't seem to work I won't be going any higher in charge, I'll just buy some H4895. BTW I'm planning on using a 168 gr HPBT bullet.

[Parashooter]

If you'll look at Hodgdon's data website, you'll find the minimum load listed for H4350 with a 200-grain Speer bullet is 50 grains, giving 2431 fps and 44,500 c.u.p. - not very far from the model with the 200-grain Sierra and 51 grains IMR 4350 (noting that the pressure there is in psi - piezo style). I wasn't suggesting a below-minimum charge.

[Bayou]

Sorry, I should have been more clear a few posts back and said that I want to use 168 gr bullets for this project. Basically because of the same reason I want to use H4350, I have plenty on hand.

[MEHavey]

Boy, if you insist on doing that make sure you have that [adjustable] gas cylinder plug open up all the way to start, then close it off a-bit-at-a-time/a-shot-at-a-time until it will 'just' function reliably.