7.62x51 in a .308 rifle

[Bart B.]

The 1976 World Palma Matches were shot in the USA using 7.62 NATO M118 match ammo. Thousands of rounds were fired in several dozen commercial Winchester Model 70 match rifles chambered for the 308 Winchester. None of the rifles got hitch in their get-along.

 

[jonnyc]

"they are NOT 308 factory size, they are 7.62 size"

Uh.....they are the same size.....your match chamber is simply tighter.

 

[Bart B.]

"they are NOT 308 factory size, they are 7.62 size"

Uh.....they are the same size.....your match chamber is simply tighter.

I've seen several dimension specs for 308 match chambers. What's the official ones?

Straight 308 cartridges (smaller than chambers) will center their shoulders perfectly in the chamber shoulder very repeatable when fired in all chamber sizes. Typically with clearance around the entire cartridge except at its shoulder's and pressure ring's chamber touch points and the firing pin's tip on the primer.

 

[Bart B.]

Further discussion of .30-06 pressure, military proof loads, the Garand and so on is off topic and I'm done being dragged into thread drift, thanks.

Bart, if you want to explore this further, why not start its own thread?

You joined this thread on your own. Nobody dragged you in.

7.62 Garands and their comparable cartridges are on topic, in my opinion.

 

[godale]

I tried to get a 783 in 308 when the original gander mountain closed . I ended up with a 300 magnum instead


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[jrothWA]

Have shot TW M80 in my Win M70, with no problems.
Basically, the bolt action will handle the pressure differance between the MILSPEC nad SAMI ammo. MILSPEC cahmbersare dimension to handle the thicker case.
MILSPEC needs to have a thicker case, due to the rapid ejection of military chambers will under the resulting pressure.
SAAMI ammo will likely tear through the extraction groove/rim or pull the case head off.

Refer to the 5.56 chamber differences between the SAAMI, WYLDE, & NATO dimension charts.`

 

[Bart B.]

Basically, the bolt action will handle the pressure differance between the MILSPEC nad SAMI ammo. MILSPEC cahmber sare dimension to handle the thicker case.
MILSPEC needs to have a thicker case, due to the rapid ejection of military chambers will under the resulting pressure.
SAAMI ammo will likely tear through the extraction groove/rim or pull the case head off.

Commercial 308 Win match ammo by the thousands loaded to 52,000 cup SAAMI max pressures fired in M1 and M14 rifles as well as commercial semiautomatic rifles never caused any problems. Military 7.62 and 30-06 ammo was loaded to 50,000 cup average.

Military M1 and M14 bolts don't start opening until bullets are 6 to 7 feet out the barrel. Pressure in the case at that time is only a few psi. Springfield Armory Technical Note SA-TN11-1094 dated 16 Dec 1957.