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Old June 23, 2018, 03:06 PM   #1
JJ45
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Loading for the PTR91

GI model in .308. 12 flutes, 1-10" twist. I think the GI has looser tolerances as far as chamber dimensions. I'm not worried about beat up brass. Besides a dent and flute marks they look okay as there are no cracks. They get dirty as pigs in a mud hole but so does the rifle Takes a lot of cleaning.

Does anyone load for one? If so, do you recommend small base dies.

My Sierra manual has a section on gas guns but although it is a semi auto the PTR is not a gas gun. I would be thankful for any advice on anything out of the ordinary when loading for this weapon.
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Old June 23, 2018, 05:39 PM   #2
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I would just stick with loads that mimic 7.62 NATO ball ammo. The 150-grain Hornady FMJ's are cheap in bulk quantity and shoot a lot better than most GI and surplus ball bullets I've seen. From Hodgdon's data, IMR 4895 at about 45.4 grains should be close on ballistics, but start with Hodgdon's 42.6 grains starting load and work up. 47.4 grains of BL-(C)2 would also mimic GI ballistics pretty simply, but, again work up from the starting load of 45.0 grains.
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Old June 23, 2018, 07:51 PM   #3
Bimus
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Winchester 7.62 mm 147 FMJ factory load
Chronograph from HK 91 at 2539 fps
Chronograph from Springfield scout Squad at 2655 fps
Chronograph from Remington 700 heavy barrel 24 inch at 2757fps


Favorite HK load Chronograph
IMR 4064 44 grains 147 gr FMJ
Military brass 2548 fps
Winchester brass 2533 fps

IMR 4064 44 grains 147 FMJ Chronograph
Springfield Scout squad
Military brass 2640 fps
Winchester brass 2621 fps

IMR 4064 44 grains 147 FMJ Chronograph
Remington 700 heavy barrel 24inch
Winchester brass 2765 fps
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Old June 23, 2018, 11:26 PM   #4
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I can't add anything significant to the load data given, but I will say this, your PTR-91 is a "gas gun". Just not in the usual sense.

Its not a gas piston gun, nor is it direct impingment in the manner of the M16, but it is gas that runs it, directly, that's why it gets so dirty.

It's called "roller locked" but tis really just retarded (delayed) blowback, and its gas that blows it back. Directly.

I've never had a PTR-91, but I had an HK 91 until I sold it in 86, the month before Patrick Purdey shot up the Stockton schoolyard the triggered the "assault weapon" hysteria we are still suffering from.

I installed an ejection port buffer to reduce the deep dent in fired brass, and did reload it, with regular dies. Don't remember the exact loads GI ball duplicate using W748 powder. I still have some of the fluted cases in my brass stash though the rifle has been gone for decades. They work fine in my other .308s...

Your rifle may be different. The gun was never designed to be reloader friendly, and that's one of the reasons I got rid of mine. That and I like my M1A better....
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Old June 24, 2018, 01:03 AM   #5
tangolima
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If roller lock is gas operated action, then nothing semi auto is not.

Loading for roller lock is pretty straight forward. The load needs to be stout enough to cycle the action, and that's about it.

-TL

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Old June 24, 2018, 05:16 AM   #6
JJ45
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Expanding gas gets it moving in any semi I think...The roller lock seems simpler though...Thanks for the loads.

Loaded for Garands and even in Sierra's manual there is a lot of cautionary advice about high primers and poorly sized brass, etc. in self-loaders,....They even advise not to load for "gas guns" I suppose the same caution applies, no matter what the action.
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Old June 24, 2018, 11:56 AM   #7
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Quote:
If roller lock is gas operated action, then nothing semi auto is not.
If you want to be precise, all guns are gas operated, without gas, the bullet goes nowhere.

All semi and full autos rely on energy from the gas to work the action. Blow back /delayed blow back do it directly, gas pressure is used to, literally, blow the case out of the chamber. There are even a couple of guns (Beretta?) that don't even HAVE extractors, they rely on gas alone, and they work just fine. (.22LR IIRC)

Gas piston and direct impingement use a portion of the gas to operate the action.

Recoil operated still needs gas pressure to work, though its not tapped directly.

The term "gas gun" is commonly used to identify those which use a portion of the gas, tapped from a port in the barrel to work the action, to easily differentiate them from recoil operated and blowback designs, but they all run on powder gas, one way, or another.

Quote:
there is a lot of cautionary advice about high primers and poorly sized brass, etc. in self-loaders,.... I suppose the same caution applies, no matter what the action
high primers and poorly sized brass is a concern in all actions, but it is a greater concern in semi's because the rounds are, literally, slammed into the chamber at a speed much higher than any manually operated action.

A "slamfire" in a bolt, lever, pump, or single shot is unheard of. Possible, I suppose, but never seems to happen. Happens in semis though....
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Old June 24, 2018, 12:24 PM   #8
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It's a roller-delayed blowback. Not that it matters. You load for 'em just like any other semi-auto. You must FL resize every time(highly unlikely to need an SB die, but it's one or the other.), check the case lengths every time(trim, chamfer and deburr as required only.) and watch the OAL.
"...a dent..." Caused by the case whacking the receiver on the way out. Nothing to worry about. It'll come out when you resize or upon firing. Case mouth dents get fixed by using needle nosed pliers to open the dent. Also nothing to worry about. Best to use the pliers as a mandrel vs prying.
A "slamfire" is caused by improperly loaded ammo, usually high primers, not the rifle.
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Old June 24, 2018, 03:12 PM   #9
libiglou
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Pretty much what everyone is saying. I just load like you normally do for 308. Two things to keep in mind with the ptr. One , it sends the brass to china your going to lose alot of them and second it mangles the bejesus out of the brass. Mine eats everything and functions fine when dirty. Just keep her well oiled.
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Old June 24, 2018, 04:13 PM   #10
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The term "gas operated" is coined for specific classification purpose. True that all energy is from gas generated by powder combustion. But it is also true that all energy on Earth is from the Sun. Following the same logic, perhaps they all should be called "sun guns".

Roller lock is much less finicky than gas operated actions when it comes to ammunitions. There is no op rod to bend, no gas orifice to plug, and even slam fire risk is almost non-existent because of its design.

Well not that it matters much as long as you follow the normal doctrines of handloading.

-TL

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Old June 25, 2018, 01:36 AM   #11
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Quote:
Roller lock is much less finicky than gas operated actions when it comes to ammunitions
While this is true, I found my HK 91 to be a bit picky about ammunition. Not the load but the brass.

the Fluted chamber system doesn't like brass that is too "soft" or too "hard". I found that USGI ammo could have issues, seems the brass is just enough "softer" than European ammo to cause this. The cases can "stick" in the chamber just enough to (sometimes) cause problems. My particular gun would do something I'd never seen before, or since. Fired slowly, it worked fine. Fired as fast as possible (semi auto) after about half a dozen or soo rounds, it would extract and empty, rotate it 180 degrees, and feed it back into the chamber.

Never did figure out how that happened but it did, and did so more than once. Never seemed to do it using European milsurp though. No idea why..really..

On the other hand, USGI ammo, oiled, worked flawlessly.
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Old June 25, 2018, 06:46 AM   #12
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Also had a HK-91, and reloaded the brass from it. The "flutes" were not a problem, but the action stretched brass more than the other semi's owned. While it could have been a situation with the specific rifle owned, it took some extra effort to resize the brass. The rollers were in spec. If memory holds, had to use sb die, or resize it twice.

Nice rifle (really nice sights), but it recoiled more than most semi 308's and stretched the brass, so I sold it.
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