Am I going to damage my M1 op rod?

[Silvercreek Farmer]

Recently started my first adventure with surplus powder. Bought 8 lbs of MP 540, a stick powder with one load listed for 308, 45 grains, 147gr FMJ. Avg. Velocity – 2700 fps., which put it right in the burn rate range for typical 308 and 30-06 service loads. I started with a bolt gun (24”) first and pretty quickly landed on 38 grains behind the Lee 170 RNFP. Shoots right 1.5”, with very consistent velocities right at 2150 fps.

I’d like to use this load in my Garand, my only concern is the ferocious muzzle blast. I can clearly see a fireball through the scope in broad daylight. I sat next to my son while he shot a group yesterday and the concussion was substantial. I would note that I was sitting next to a wall in the shooting house and have not fired a full power 30-06 in years, and most of our shooting is with Alliant 2400 these days. But, we did fire some full power 7mm mag last week in the shooting house and I did not notice this much flash or bang.

Is it just that this powder is not flash suppressed? Or a reduction of burning efficiency in the reduced load leaving a bunch of powder to burn in front of the muzzle? Either way, just want to make sure I am not going to damage my Garand.

Is spent casing ejection distance any indication of over gassing a Garand? If so, how far is too far?

[Baltimoreed]

Get a adjustable gas plug, open it all the way, shoot your loads and adjust it back down until your garand ejects the cases. If you change the load readjust the plug. How do your primers look?

[Ford SD]

Not a expert on that powder .... But I would be using the correct speed range powder for the M1 garand ie 4895

Save that powder for the bolt guns

All you need for a m1 Garand is Powder in the correct speed range and the gun to 100% function and the brass not to be flung far away.. as its easier on the rifle and easier on the brass

[derek45]

get some 4895 for your Garand

[osage]

I purchased an adjustable gas plug but haven't used it yet. I understand the desire or need to load what powder you have access to. I found a reference on another forum in regards to burn rate of 104 to 110 for MP 540. IMR 4895 is at 121.

[Silvercreek Farmer]

Get a adjustable gas plug, open it all the way, shoot your loads and adjust it back down until your garand ejects the cases. If you change the load readjust the plug. How do your primers look?

Primers look fine.

[Baltimoreed]

That’s good but I still would invest in a Shuster [i think] gas plug if you cant get 4895. Cheaper than an op rod. I don’t reload for my garand anymore since I was gifted a couple gi ammo boxes of LC ball.

[TNsailorman]

Original OP rods are getting harder and harder to find now days. Especially ones that are not worn too much. They can be repaired though by someone who knows what he is doing. But why take a chance on maybe ruining one when it is not necessary.

[Ford SD]

Is spent casing ejection distance any indication of over gassing a Garand? If so, how far is too far?

the Garand Has a weird ejection Pattern it depends ????

Does Brass hit Oprod Hump ??? Yes / no .... it can go anywhere front ... to the side .. Back ..

is it last Round ? Yes / no .... it can go anywhere ... to the side ..or Back ..

it can also depend on the speed of the bolt and the little ejector spring

Distance .. Closer the better as you can find more in the grass


http://bulletin.accurateshooter.com/2015/12/cool-slow-motion-video-of-m1-garand/

[georgerkahn]

I strongly agree with other posters suggesting you invest in a replacement gas plug! I have and have used the Schuster -- WELL worth the money if compared to potential damage to your firearms and -- if you're lucky -- repairs to the Op Rod by the firm who specializes in fixing them (they advertise in the Garand Collectors Assn. magazine).295712 The M1 Garand is a funny duck in that not only the pressure from burning powder needs to be right on, but also the curve at which it burns.

[Silvercreek Farmer]

Alright, gas plug ordered. Don’t want to hurt the old girl!

[AlaskaMike]

Unfortunately I can't comment specifically on the MP 540 powder because I have no experience with it. However, based on many of the replies so far, I do have some other comments.

The often prescribed 4895 powder for use in the Garand really only applies to jacketed service type loads. When you switch to using cast bullets, everything changes, and the "normal" rules simply don't apply anymore. This should come as no surprise to anyone who has ever read a handloading manual. If you change one component, you need to reevaluate things.

When we talk about proper powder burn rate for the Garand, you have to keep in mind that we're talking about the pressure at the gas port. When we're talking about a 147-168 grain jacketed bullet at about 2700 fps, then we're looking at powders like 4895, Varget, 4064 and similar ones.

However, when we want to switch to a cast bullet of similar or even heavier weight, we want to drop the velocity to something optimal for cast bullets. So then we drop our (for example) charge of 47 grains of IMR-4895 down to 35 grains. This puts us in the target velocity range of about 1600 - 2000 fps. However, at this point we've also dropped the pressure at the gas port to less than the required ~8k psi, so the action doesn't cycle fully. It may eject the spent brass but not chamber the next round. Or it may not even eject the brass. So then what do we do? We start looking at slower powders to get back to that required port pressure to reliably cycle the action, and yet still remain in that 1600 - 2000 fps velocity range.

Powders like 4350 and 4831 are entirely useful and safe when used with cast bullets in the Garand at lower cast bullet velocities.

I recognize that some folks will jump all over me and accuse me of heresy with that statement. So be it. I've developed loads with both H4350 and H4831sc and 190-200 grain cast bullets that are not only accurate, but also are very gentle on the op rod.

The sad fact is that a member here, BruceB, who is no longer with us, did quite a bit of development in this area and documented it well, and it's disappointing to me to see that his work seems to be largely forgotten and overlooked now. The thread is here: https://castboolits.gunloads.com/showthread.php?3558-7-62x51-NATO-(-308-WCF)-in-the-Springfield-M1A

Bruce started out working on cast loads with his M1A, but then also expanded it to include his Garand. Unfortunately, even though that thread is a sticky in the CB Loads for Military Rifles forum, it seems that very few folks these days have read it. For those wanting to shoot cast in the M1A or Garand, and want their loads to cycle the action, that thread should be required reading.

[Kraschenbirn]

+1 on what Mike said. I've fired a couple thousand rounds using AA2700 behind powder-coated Lee 311-200s without a glitch. At 1970 fps, accuracy pretty much equals M2 Ball with a lot less wear and tear on my Garand.

Bill




\

[Silvercreek Farmer]

Unfortunately I can't comment specifically on the MP 540 powder because I have no experience with it. However, based on many of the replies so far, I do have some other comments.

The often prescribed 4895 powder for use in the Garand really only applies to jacketed service type loads. When you switch to using cast bullets, everything changes, and the "normal" rules simply don't apply anymore. This should come as no surprise to anyone who has ever read a handloading manual. If you change one component, you need to reevaluate things.

When we talk about proper powder burn rate for the Garand, you have to keep in mind that we're talking about the pressure at the gas port. When we're talking about a 147-168 grain jacketed bullet at about 2700 fps, then we're looking at powders like 4895, Varget, 4064 and similar ones.

However, when we want to switch to a cast bullet of similar or even heavier weight, we want to drop the velocity to something optimal for cast bullets. So then we drop our (for example) charge of 47 grains of IMR-4895 down to 35 grains. This puts us in the target velocity range of about 1600 - 2000 fps. However, at this point we've also dropped the pressure at the gas port to less than the required ~8k psi, so the action doesn't cycle fully. It may eject the spent brass but not chamber the next round. Or it may not even eject the brass. So then what do we do? We start looking at slower powders to get back to that required port pressure to reliably cycle the action, and yet still remain in that 1600 - 2000 fps velocity range.

Powders like 4350 and 4831 are entirely useful and safe when used with cast bullets in the Garand at lower cast bullet velocities.

I recognize that some folks will jump all over me and accuse me of heresy with that statement. So be it. I've developed loads with both H4350 and H4831sc and 190-200 grain cast bullets that are not only accurate, but also are very gentle on the op rod.

The sad fact is that a member here, BruceB, who is no longer with us, did quite a bit of development in this area and documented it well, and it's disappointing to me to see that his work seems to be largely forgotten and overlooked now. The thread is here: https://castboolits.gunloads.com/showthread.php?3558-7-62x51-NATO-(-308-WCF)-in-the-Springfield-M1A

Bruce started out working on cast loads with his M1A, but then also expanded it to include his Garand. Unfortunately, even though that thread is a sticky in the CB Loads for Military Rifles forum, it seems that very few folks these days have read it. For those wanting to shoot cast in the M1A or Garand, and want their loads to cycle the action, that thread should be required reading.

Thanks. It has been a while, but I have read it. That’s pretty much what I figured when I bought the powder, that even if the burn rate was a bit on the slow side, the port pressure would be alright given the reduced load. I just got a bit nervous when I saw those fireballs!

[fastdadio]

Service rifle loads;
http://bearblain.com/Service%20Rifle%20Loadings.html
Personally, I stick with proven loads/powders for my Garand/M1a. A starting load of 39 grs H4895 with the Lee 170 cycles my Garand reliably, groups under 3"@ 100yds, lays the brass at 2 o'clock, and is easy on the ole girl.

[derek45]

Make sure she has a new recoil spring ( not "extra power" ) ang grease, not oil. I use MOBIL1 bearing grease.


From the old NRA Garand book

https://i.imgur.com/PXxLwZw.jpg

https://i.imgur.com/qcbUvbF.png

https://i.imgur.com/La4m45q.jpg

[Silvercreek Farmer]

Service rifle loads;
http://bearblain.com/Service%20Rifle%20Loadings.html
Personally, I stick with proven loads/powders for my Garand/M1a. A starting load of 39 grs H4895 with the Lee 170 cycles my Garand reliably, groups under 3"@ 100yds, lays the brass at 2 o'clock, and is easy on the ole girl.

Thanks for the link. My charge weight and velocity are consistent with starting loads for the 180 grain data. It’ll be interesting to see how far closed I get the gas plug before it cycles, I bet it will be nearly closed.

[fastdadio]

Thanks for the link. My charge weight and velocity are consistent with starting loads for the 180 grain data. It’ll be interesting to see how far closed I get the gas plug before it cycles, I bet it will be nearly closed.

I wouldn't even try to guess. Never heard of the powder you're using. But keep in mind the the advice given above. With the M1's, it's not about muzzle velocity, but the port pressure at the piston that needs to be kept in range.
Oh, and you're most welcome on the link.