Mk 248 Mod 0 help!

[LongRange98]

Hello folks. I found a good deal of this Mk 248 Mod 0 190 grain smk for my .300 win mag custom bergara. However after doing some research it’s not clear to me if it’s safe to fire or not. I know Mod 1 is not recommended but not much info on the Mod 0. Can anyone help me out? Thanks!

 

[FatBoy]

It’s basically gold medal match ammo. What’s your concern?

 

[LongRange98]

That the OAL is out of sammi spec as well as the powder charge is about 4 grains over what my reloading manuals state.

 

[nn8734]

Some relevant info comparing the two mk248 variants.

US Army Selects Sig Sauer to Manufacture .300 Win Mag Sniper Ammo — Potts Precision

Discussing Sig Sauer’s contract to manufacture the Mk. 248 .300 Win Mag ammunition for US Army sniper rifles.

www.pottsprecision.com

 

[Riverlife87]

Send it

 

[RegionRat]

That the OAL is out of sammi spec as well as the powder charge is about 4 grains over what my reloading manuals state.

Starting with the folks who set the philosophy of going into high pressure with M855A1, you can't count on MIL committees to stay in pressure ranges that were associated with historical SAAMI specs for ammo or guns.

They accept shortened gun life and they don't care about reloading either so brass life means nothing to them.

The only way you will know what works for you, is to run a load development that meets your needs.

The idea that pressure can go high enough to cause premature brass failure and yet at the same time not rupture the case or primer, means some committees will go there but you don't have to follow them if you don't want to.

Ammo like this can be high enough to cause extraction problems in some guns, yet not in others.

If you don't want to run pressure that is so high that it ruins brass, then you don't have to but that means you are doing the loading.

 

[LongRange98]

Starting with the folks who set the philosophy of going into high pressure with M855A1, you can't count on MIL committees to stay in pressure ranges that were associated with historical SAAMI specs for ammo or guns.

They accept shortened gun life and they don't care about reloading either so brass life means nothing to them.

The only way you will know what works for you, is to run a load development that meets your needs.

The idea that pressure can go high enough to cause premature brass failure and yet at the same time not rupture the case or primer, means some committees will go there but you don't have to follow them if you don't want to.

Ammo like this can be high enough to cause extraction problems in some guns, yet not in others.

If you don't want to run pressure that is so high that it ruins brass, then you don't have to but that means you are doing the loading.

Makes sense thank you for your knowledge.

 

[LongRange98]

Some relevant info comparing the two mk248 variants.

US Army Selects Sig Sauer to Manufacture .300 Win Mag Sniper Ammo — Potts Precision

Discussing Sig Sauer’s contract to manufacture the Mk. 248 .300 Win Mag ammunition for US Army sniper rifles.

www.pottsprecision.com

This was useful it seems Mod 0 is safe Mod 1 needs more caution. Thanks for the article.

 

[FatBoy]

I’ve had no issue with the few Mod0 lots I’ve shot. The mod1 also shot very well but the brass was unusable.