Greetings all. I have expanded by reloading activities into rifle rounds, and am trying to pre-empt a possible safety issue. I am loading 147gr FMJ BT .308 diameter bullets into various .308 brass. Powder recommended for me by the local shop is IMR 4320. Maker: IMR Powder in Shawnee, KS. I know they can't list every bullet weight, the closest they come is two 150gr jacketed bullets, one at (start load) 43.7gr IMR, the other at 44.7gr IMR. I have Lee and Sierra reloading manuals that do not list a 147gr bullet, but also list the 150gr as the closest projectile. My projectile will be 3 gr lighter in weight. Will there be a safety issue here that will require me to back off 10% in my starter loads? BTW both rifles this is intended for are semi-auto, so there must be enough "oomph" to move the operating rod back smartly.

quote:

Originally posted by SSI01:
Greetings all. I have expanded by reloading activities into rifle rounds, and am trying to pre-empt a possible safety issue. I am loading 147gr FMJ BT .308 diameter bullets into various .308 brass. Powder recommended for me by the local shop is IMR 4320. Maker: IMR Powder in Shawnee, KS. I know they can't list every bullet weight, the closest they come is two 150gr jacketed bullets, one at (start load) 43.7gr IMR, the other at 44.7gr IMR. I have Lee and Sierra reloading manuals that do not list a 147gr bullet, but also list the 150gr as the closest projectile. My projectile will be 3 gr lighter in weight. Will there be a safety issue here that will require me to back off 10% in my starter loads? BTW both rifles this is intended for are semi-auto, so there must be enough "oomph" to move the operating rod back smartly.

"Were it me" I would use the 150gfmj data & not worry about my safety factor being to great? IMR 4064 is a good powder also. 150g starter loads is where I would start

No. Backing off starter loads 10% is SOP.

147, 150; same thing. Three grains is not important. Use the 150 grain data. You didn't say what kind of rifle you had, but Hornady lists loads just for semi autos; you don't what to over gas an M1; you can bend the operating rod; remember they were made for M2 Ball Ammo; Not modern 30-06 pressures.

Indeed. A local gunsmith told me the same things you fellow did a couple of days ago. 3 grains? Not worth worrying about, my bullet is the 147gr military bullet and is slightly lighter than the 150gr, smith says the difference is insignificant and the load mentioned by IMR is a mid-range load. I liked to load at that point when I did this before; I don't like to strain either the rifle or the brass.

You're right, I didn't mention what rifles I'll be using w/this round - my son left me a new M1A; I've had a Tanker Garand chambered in .308 Win. for almost 50 years, but seldom fired it. They're both semi-autos so as has been intimated I've got to produce enough pressure to cycle the op rod without bending it. I figured a mid-range load as set forth by the powder manufacturer is the way to go. I can go up or down from there. I did fire reloads in the Tanker Garand, have had it apart since then and the operating rod, which has an odd appearance as it is so short compared to that of a full-sized M1, still is straight, shows no signs of bends or cracks after some really close checking.

I thought about moving the charge down ever so slightly due to the lighter weight of my chosen bullet, but then that would mean keeping the gas in the barrel and op rod cylinder just that much longer so decided against it. The rifle's action needs to move smartly if it's to function at all, just can't be "slammed" back by a hot load. That means getting the bullet out safely without undue strain on the weapon. So I will use a mid-range load to that end, don't like hot-rodding or experimenting with these things.

Another powder you might consider for your rifle: IMR 4895

You might look over some of the posts on M14 Forum in their reloading/ammo section. Like a lot of sites, they have recently "upgraded" and it's not as easy to use as it was in the old days.

OP: you may want to look up Glen Zediker's Reloading for the Match M14. It doesn't give much for load data, but is a very good overview of reloading for the M14 style rifles.

While it may work for him, I have never needed to use small base resizing dies in any of my service rifles.

What Leonard said. Read Zediker's piece, was originally a chapter in a Sierra manual.

"Various" with respect to .308 brass is a concern. Bulk sourced stuff fired from MGs may be seriously overstretched, some pieces. Even if you get it sized to chamber, the damage was done on first firing - there's an impending separation ahead. You can use your chamber to check after sizing attempt, but alot easier to find these pieces before processing using something like a Wilson gauge. Watch TV, even, do it by feel. Fired cases that are badly overstretched are obvious. Once-fired from your rifle and skip all I just wrote.

Which "semi-auto" also matters. M-14 one of the more burn-rate picky guns. AR-10 or G3 less picky.

Here is Hornady's load data for the 308 Service Rifle and for the M1 Garand:





Okay couple things. The M1A isn't a M14. The manual that comes with the M1A (Which I have the National Match Model with stainless barrel) states for ammunition to be used as ALL 308. You all know the 308 Win is loaded to a much higher pressure then the 7.62 NATO. Springfield designed the M1A to shoot the 308 Win loads. As for the Garand there have been 308 Garands from WAY back. The gas port hole is adjusted for each caliber. I've seen M1 Garands chambered out in everything up to 458 Win Mags. Put this all aside. If you're worried about bending and op rod buy yourself an adjustable Schuster valve that replaces the the original gas piston cap on the M1A and the chamber cap on the Garand.

The best powders for the 308 are 4895, 4064, and 748. The first two or great for the 30-06 too.

You can buy that valve at many places, but here's one at Midwayusa:

https://www.midwayusa.com/product/100471950

quote:

Originally posted by vzerone:
Okay couple things. The M1A isn't a M14. The manual that comes with the M1A (Which I have the National Match Model with stainless barrel) states for ammunition to be used as ALL 308. You all know the 308 Win is loaded to a much higher pressure then the 7.62 NATO. Springfield designed the M1A to shoot the 308 Win loads.

This is an excellent point. Also applies to the G3/HK91. Some guns built off G3 parts kits will have 7.62x51 NATO fluted chambers. Not for commercial .308 Win pressures and brass thickness.

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Originally posted by Samuel_Hoggson:

quote:

Originally posted by vzerone:
Okay couple things. The M1A isn't a M14. The manual that comes with the M1A (Which I have the National Match Model with stainless barrel) states for ammunition to be used as ALL 308. You all know the 308 Win is loaded to a much higher pressure then the 7.62 NATO. Springfield designed the M1A to shoot the 308 Win loads.

This is an excellent point. Also applies to the G3/HK91. Some guns built off G3 parts kits will have 7.62x51 NATO fluted chambers. Not for commercial .308 Win pressures and brass thickness.

Sam I argued this point with a fellow that is so convinced that a forged receiver is so much stronger and better then a cast one. Well Springfield casts their M1A receivers. What their rifle can shoot and take the punishment sure speaks for itself. Who knows maybe the M14's could take more. That would make for a good test between the two. You know I was shocked too that my manual didn't say anything about reloads!!!!

That is just more hype and advertising nonsense; the Investment cast receivers are as strong as a "forged" one.
One point though; the OP was worried about over gassing an M1A with lighter/slower loads; that is impossible; the M14 gas piston design cuts the gas off immediately once it starts moving. So no more gas can get into the cylinder no matter how slow the bullet is or how long the gas is in the barrel, it is "cut off". You an also completely cut the gas off using the spindle valve, but that is another thing.
The Garand (M1 Rigle), OTOH, has no such cut off system and gas can fill the cylinder, but since it is close the the muzzle, you get the idea.
I blew up an M14 once, filled a case with blank powder. I recommend no one else do that. It broke the bottom half of the bolt face off. Long ago.

I didn’t see anyone mention (I’m using a phone now so sorry if this was stated) that military brass is usually thicker/heavier and that you will need to cut loads a bit to deal with the pressure increase from reduced case usable volume.

Also, unless you have a swaging device for the military crimp, that can cause real headaches for reloading.

I would start 20% off the load in military brass and work my way up in 1 grain increments until you get good function.

If you don’t have a chronograph, stop there once you have good function.

I’ve mostly used Varget, 748, and 4895, but starting to use some 4064, that seems to shoot surprisingly well also.

quote:

Originally posted by dpcd:
That is just more hype and advertising nonsense; the Investment cast receivers are as strong as a "forged" one.
One point though; the OP was worried about over gassing an M1A with lighter/slower loads; that is impossible; the M14 gas piston design cuts the gas off immediately once it starts moving. So no more gas can get into the cylinder no matter how slow the bullet is or how long the gas is in the barrel, it is "cut off". You an also completely cut the gas off using the spindle valve, but that is another thing.
The Garand (M1 Rigle), OTOH, has no such cut off system and gas can fill the cylinder, but since it is close the the muzzle, you get the idea.
I blew up an M14 once, filled a case with blank powder. I recommend no one else do that. It broke the bottom half of the bolt face off. Long ago.

That's interesting about blowing up a 14. Other then the bolt no other damage? Like I said they probably made the 14 more then strong enough even for 308 cartridge.

I was going to mention the 14's had that gas vent, but figured it might raise shackles. OTOH on the M1 Garand piston, after it moves a certain amount of distance, vents the gas off down the tube the piston/opt-rod ride in. It'll make your sling dirty with certain loads. Ask me how I know.

quote:

Originally posted by crbutler:
I didn’t see anyone mention (I’m using a phone now so sorry if this was stated) that military brass is usually thicker/heavier and that you will need to cut loads a bit to deal with the pressure increase from reduced case usable volume.

Also, unless you have a swaging device for the military crimp, that can cause real headaches for reloading.

I would start 20% off the load in military brass and work my way up in 1 grain increments until you get good function.

If you don’t have a chronograph, stop there once you have good function.

I’ve mostly used Varget, 748, and 4895, but starting to use some 4064, that seems to shoot surprisingly well also.

I would assume that most knowledgeable reloaders would know that about the brass being thicker in the military version. I wouldn't work up in 1 grain increments I'd do 1/2 gr.

The primer pockets are no big deal on military crimped brass. You can ream it out even with the tool you use to deburr the inside and outside of the case mouth. You can also remove the crimp with a pocket knife. I use the RCBS swage remover which works very well.

I've been doing some research on IMR 4320 powder in .308/.30-06 as an alternative to some medium-burn-rate powders already listed in a few places. An article in AccurateShooter.com says 4320 is an acceptable substitute for Reloder 15, Varget, and H4895 powder except it can be more temperature-sensitive than the other three powders, and allowances should be made for ambient air temperature possibly affecting the cartridge case.

I have two bottles of IMR 4320 to hand, but I'll be stopping by the gun shop later today to see if I can find any of the other three powders mentioned above. My Sierra Edition VI manual says special attention should be paid to .30-06 loads for the M-1, you should not be using a quick-burning powder in that rifle and the op rod is sensitive to that. I was planning on using 4320 in the .308 loads I'm going to be rolling, all the brass is commercial (I checked the headstamps - all 500 of them). Mid-range loads only to be loaded. What I've seen here indicates the M1A should stand up pretty well to that combo (4320/147Gr GI bullet), but my concern is in using the same ammo in the .308 Garand I have. Since I wanted to use the same powder in the .30-06 loads I haven't started on yet, I wanted to make sure 4320's burn rate is acceptable in an M-1 using a mid-range load as well. Trying to stay within the topic of .308 here, sorry. I will ask detailed questions re: .30-06 in a separate posting if required.

Also just picked up a Schuster valve for the Tanker Garand, I can't be sure that thing's gas port in the barrel is made for a .308 powder charge or a .30-06. It's a National Ordnance weapon so there is the possibility the barrel is still ported for an M-1 op rod when we're dealing w/a .308 round here. Figured the Schuster valve would let me tailor the gas expansion a little for use w/the smaller round. Will start w/fully open valve and adjust from there until function is smooth and clean.

quote:

Originally posted by SSI01:
Also just picked up a Schuster valve for the Tanker Garand, I can't be sure that thing's gas port in the barrel is made for a .308 powder charge or a .30-06. It's a National Ordnance weapon so there is the possibility the barrel is still ported for an M-1 op rod when we're dealing w/a .308 round here. Figured the Schuster valve would let me tailor the gas expansion a little for use w/the smaller round. Will start w/fully open valve and adjust from there until function is smooth and clean.

IMR 4895 and IMR 4064 have been the target loads for 308 from the M1A/M14 and also for the 30-06. Fast powders to me, in the IMR line is 4198 and 4227. I know a lot of guys like 3031 in the 30-06 and to me that's little on the fast side. I shot IMR 4320 for years mainly in 243 Win.

The M1A's are made for any 308 ammo according to Springfield's owners manual. I'm not sure what they did for 308 Garands. I'm pretty sure they didn't mess with the gas port hole on the ones they put a chamber insert in the 30-06 chamber to accept 308's. Now the ones built from the ground up for the 308 may have had attention paid to the gas port size.

The way I heard it for the 06 Garand was not to shoot heavy loads with heavy bullets using slow burning powder. Those are what can bend the op rod. The Schuster valve eliminates all that. The M1A/M14 have a gas bleed off hole in the gas cylinder so pretty hard to mess up the op rod on those in addition to them being short and stouter.

Thanks vzerone. I was thinking along those exact same lines w/the M1 but needed someone else to confirm I seemed to be on the right track. Moderate-burn-rate powder, 147gr FMJ bullet on 150gr data, and mid-range loads will be the way to go for the M1. Just make sure the op rod cycles without being slammed around and you should be OK. BTW went by the gun shop - no new powder in stock, not likely to be any more for some time now. I found some Winchester 748 ball powder that is recommended in the Lee 2nd Edition for .308 Winchester AND .30-06, including in the Garand. Lee 2nd edition shows a max load of 49gr/C of IMR 4320 for a 150gr jacketed bullet, 2936FPS, start load of 44.1gr for 2658FPS; I plan on settling at about 46gr and seeing how that performs.

Sorry - should have said that 4320 data will apply to the .308 rounds.

quote:

Originally posted by dpcd:
That is just more hype and advertising nonsense; the Investment cast receivers are as strong as a "forged" one.
One point though; the OP was worried about over gassing an M1A with lighter/slower loads; that is impossible; the M14 gas piston design cuts the gas off immediately once it starts moving. So no more gas can get into the cylinder no matter how slow the bullet is or how long the gas is in the barrel, it is "cut off". You an also completely cut the gas off using the spindle valve, but that is another thing.
The Garand (M1 Rigle), OTOH, has no such cut off system and gas can fill the cylinder, but since it is close the the muzzle, you get the idea.
I blew up an M14 once, filled a case with blank powder. I recommend no one else do that. It broke the bottom half of the bolt face off. Long ago.

Here's what I'm interesting on that blow up test you did on the M14. Did the lugs on the receiver get set back with the test that you did? What shape were the lugs on the bolt? Thanks in advance.

quote:

Originally posted by dpcd:
147, 150; same thing. Three grains is not important. Use the 150 grain data. You didn't say what kind of rifle you had, but Hornady lists loads just for semi autos; you don't what to over gas an M1; you can bend the operating rod; remember they were made for M2 Ball Ammo; Not modern 30-06 pressures.

How about the 96 Swedes? They were made for the 6.5x55 Swede, yet Kimber refurbished the actions and put new barrels on them and sporter stocks and sold them...and they chambered them for modern higher pressure cartridges then the 6.5 Swede. Did they do anything to strengthen the action???? I don't believe they did and to boot they drill and tapped the front receiver ring for scope base with in my opinion could weaken it. Never heard of any blowing up. Me thinks some of these old war veterans were far stronger then needed for the intended cartridge they shot. I already mentioned that the Garand action was made of a special forged steel alloy. Far far stronger then any 30-06 load would produce WW2 or modern day.