Letter: Soft Point Ammunition in a PTR-91

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Dear Mister Rawles,

To your knowledge, does 308 soft point ammunition function in a PTR-91?

JWR Replies: Just like the HK91 from which it is cloned, the PTR91 is not specifically designed to shoot .308 Winchester softnose hunting ammo. The SAAMI specifications for commercially-loaded (Remington, Winchester, Federal, et cetera) .308 Winchester are different from the military specifications for 7.62mm NATO. Although the two cartridges have quite similar exterior dimensions, the military brass is thicker (this creating slightly smaller interior dimensions) and the pressure specification is lower. (Yet, I still hear people talk about “hot military ammo.” The reality is just the opposite; the commercial loads have considerably higher pressure than the military loads.)

Now, as for the HK91/PTR91 design: It has been reported that these rifles will shoot .308 Winchester without damaging the action. However, keep in mind that this action uses a fluted chamber, and that it is notorious for violently ejecting brass. (It is not unusual to have an HK eject fired brass 20 feet, or farther!) With the thinner .308 commercial brass, it is therefore inevitable that you will someday see a case failure, resulting in a jam. Here are a couple of ways this can happen:

Typically, a case failure will leave the front half of the brass while the back half is ejected. Then when a new round is chambered, the bolt will not fly close. Clearing that stoppage does not usually solve the problem, since there is still half a cartridge case in the chamber. It can only be cured by either waiting for the gun to cool down and cycling the action repeatedly and/or banging the rifle’s butt, or by using a ruptured case extraction tool.

The other likely failure is a rim failure, where 95% of the case is left lodged in the chamber. One small portion of the rim shears off, and then the extractor can no long “catch” the empty case. This also can result in a broken extractor.

Bottom line: Yes, you can use .308 softnose in an HK or clone, but DO NOT do so in life threatening situations because jams can take a long time to clear.

Lastly, be sure to buy a spare extractor and a few extractor spring cotter pins for your rifle. These parts are available from RTG Gun Parts, and several other online HK parts dealers. Buy a spare firing pin and a couple of spare takedown pins, while you are at it. (In fact, RTG’s $116.95 \ is worth buying.)

Another must is buying a .308/7.62 NATO ruptured case extractor tool. These are available from KeepShooting.com

I should also mention that there is also an issue of the shallow depth of the chamber flutes used in early-production PTR91 barrels. This makes their early rifles more finicky on the ammo that they will feed. With those, I have found that military surplus South African, German, and Lithuanian ammo all feeds and ejects reliably. And as Pat Cascio pointed out in his review of the PTR91, Winchester (“USA”) white box 7.62mm ball ammo does not function reliably in early PTR-91s.

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