CMP Warning

A

Aguila Blanca

Staff
I received TWO e-mails today from the CMP. Both forwarded a warning about using hot or heavy loads in M1s and 1903 rifles. Most of you probably already are aware of this, but I'm posting it as a general advisory.

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Beats me, but they sent one e-mail in the morning and another later in the day, so somebody at the CMP HQ must think we need to know this.
 
Contrary to what the warning says, I have always been under the impression that the 1903 Springfield was designed for a cartridge with a 220 grain bullet.
 
Someone may be having a problem with sentence construction.

It's an AND condition:

- Loaded beyond 50,000 CUP*
~~ AND ~~
- Has a bullet weight more than 172-174gr

*SIDENOTE: SAAMI specifies
50,000 CUP <--> 60,000 psi



But I'm always wiliing to be shown the error of my ways.....
 
I know guys who hunt hogs with their Garands. They use 180gn or 220gn 30-06 hog-slammin' loads.

Zero issues ... and a lot of DRT hogs. Why? Because all factory '06 ammo is loaded below the 50,000 CUP pressure limit. Bullet-weight is irrelevant.

Heck, the .308 Win cartridge has a 52K CUP limit. Guess how many Garands are out there running .308 barrels, like the old Navy Garands. In fact, many of the more recent .308 M1s in circulation were built and sold by the CMP themselves using modern Criterion barrels.

Plus, IIRC, 7.62mm surplus ammo, which a .308 M1 can also shoot, is actually CUP-rated below .308 Win, like a 50K max, I believe.

Do you think the CMP honchos will be issuing a "recall" on any .308 Garands they sold because the cartridge they're chambered for has a 52K max pressure limit? :rolleyes:

If you're still goosey about shooting heavier-than-172gn bullets in your M1, just remove the GI gas plug and install one of the adjustable gas plugs on the market. Get out to the range, tune in your load of choice by dialing-in that internal screw in the plug.

Problem (or non-problem) solved. Easy-peasy.

You can thank me later. :cool:
 
It is not the bullet weight or the chamber pressure that is concerning.
It is the port pressure. A full charge load of slow burning powder - like you would tend to pick for top performance with a heavy bullet - will give greater than design port pressure and can bend the hard to replace operating rod.
 
The USAF developed and USN load for 7.62 Garands at 600 yards to 1000 was 44 grains of IMR4320 under Sierra' 190's in new M118 match cases.

Commercial 30-06 match ammo for Garands often used 180 grain bullets.
 
I have always been under the impression that the 1903 Springfield was designed for a cartridge with a 220 grain bullet.
Click to expand...

It was. It was designed to use the .30-03 round which was originally loaded with the 220gr bullet used in the .30-40 Krag.

When the 30-06 replaced the .30-03 and used a lighter bullet, there was no change to the actions, just the barrels.
 
Jim Watson said:
It is not the bullet weight or the chamber pressure that is concerning.
It is the port pressure. A full charge load of slow burning powder - like you would tend to pick for top performance with a heavy bullet - will give greater than design port pressure and can bend the hard to replace operating rod.
Click to expand...

Exactly so.

Port Pressure - is the only issue.




Red
 
The "warning" is not in any way new "news". I think its just somebody at the CMP doing an extra layer of CYA.
 
It might be some hog hunter shooting 220 gr loads using full case 4831 loads bent his op rod and then whined to CMP they sold him a gun that was defective.

I don't know for sure,but it might be that a Navy Shooting team has armorers ,tuners,testers,and bins of parts to develop winning combinations that work.

Most folks don't have those resources. I'm figuring on my op rod lasting longer than I do.

There are hollowed out gas cylinder lock screws and adjustable ones. Both can be a remedy. So far,I've used H-4895 and 168 gr BTHPs . I'm not pushing anything. I'm not going to worry about it.

Its also true that the modern crop of 1903/1903A3/ 1903A4 rifles that people are shooting at CMP games are resurrected previously de-activated drill rifles. CMP knows that.
I built a 1903A4gery on one. It shoots fine. I don't think I'll try to push it too hard.

Gamers always push whatever limits they can . It might be the CMP just wants to keep things safe and have a prudent paper trail.
 
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Gamers always push whatever limits they can . It might be the CMP just wants to keep things safe and have a prudent paper trail.
Click to expand...

A couple of 1903s shot at the CMP Talladegha old-school matches have imploded from idiots using hot-rodded .30-06 reloads.

That said, Shuff's Parkerizing builds 16" Mini-Gs (M1 Garands chopped to "carbine" length) in .35 Whelen.

He installs an adjustable gas plug to tune the action to cycle reliably while protecting the op rod and gas system from excessive pounding from the Whelen rounds. It's the Schuster Mfg. plug, I think.
 
Now they tell us. Been loading my 1903 with 180gr bullet's since I got it in 1995. also no clue on pressure, let pressure signs guide me. Seem's to me the original 30-06 load was a 220gr bullet later changed to a 150gr.
 
Originally Posted by JustJake View Post
A couple of 1903s shot at the CMP Talladegha old-school matches have imploded from idiots using hot-rodded .30-06 reloads...
Click to expand...

Wow, that must have been really something! How did they get them to implode??? :rolleyes:
 
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