What High Pressure Looks Like

[Walkalong]

Paper-Patched bullets.

 

[Slamfire]

My personal approach to straightness is to not resize. Instead, I use a paper sabot to hold the bullet in the case. I also lube the bullets by placing a smear of bullet lube on a cardboard wad that goes under the sabot. It seems to work quite well, particularly with the long necked hornet.

peterotte: I find this interesting. You ought to start a new thread, and show us with some pictures how you do this. And if you have done any chronographing and on target groups.

 

[Gewehr98]

I guess if you're trying to get every last bit of performance out of a round...

Then you bump up the pressures accordingly. Obviously, with all that brass flowing into the extractor hole they're well past SAAMI limits. Luckily, Uncle Sam doesn't carry insurance, they just pay in cash. If they blow up a soldier or Marine in the process, he'll head off to the military hospital, and another will step in to continue where the first left off.

Reminds me of my days in IPSC when .38 Sooper was the rage, but they wanted it to make Major Power Factor. So it got boosted considerably, and the brass looked like it was ready to let go, just like the stuff in the above pictures.

 

[The_Antibubba]

Originally Posted by SlamFire1

Both of these elite shooting teams shoot commercial loaded ammunition out to three hundred years.
---
Good Lord! If they're getting relativistic velocities, no wonder the brass is showing pressure signs.

One point twenty one gigagrains!?!?

 

[peterotte]

SlamFire1 I will do. Just got get out to the range with a chrono and a whole batch of test ammo. Been doing a bit of hunting lately - taking up my time.

Regards
Peter

 

[NateG]

For those who discount factory ammunition, one of the Armorers told me "I don't know why we are not using the 69's, I set a number of national records with that." I have observed the rapid fire groups of AMU and USMC shooters and can tell you, premium factory ammunition will shoot perfect groups. Wish I had a camera which could show you the knots these guys shoot.

Here's a picture of SFC Singley's 200 sitting group from the NTI this year. He ended up third.

 

[Harley Quinn]

I found this site about the 69gr.:

http://www.lapua.com/uploads/media/ProductBrochure223Rem.pdf

These are for the true "marksman" I'd say, or as the USMC would mention the Experts.

 

[carnaby]

Is that target shot with Iron sights???

 

[Slamfire]

Is that target shot with Iron sights???

That target was shot with iron sights on a "Service Rifle". From about ten feet away the NRA service rifle looks like a service rifle, but it has a free floating handguard, better trigger, heavy barrel, and match sights. The AMU and USMC are shooting M16 receivers, civilians make do with the AR lower.

And it is totally amazing what these guys can do. The 200 sitting RF is ten shots in 60secs, with a reload, from standing.

Try it sometime.

 

[carnaby]

I can barely manage a group like that seated, in 10 minutes, with my hunting rifle and a 9x scope. I gather that the "200" implies 200 yards, no? Wow.

How much "better" are the M16 receivers than the civilian stuff?

 

[Howard Roark]

They are no better.

 

[wanderinwalker]

SF1,

Winchester commercial brass will start to show the beginnings of those signs at about 2700-fps in my rifle. My experience is that with most brass and powder combos, anything over that is definitely a hot load. Those military teams loads are nuclear loads, eh?

For those who asked, the 80gr Sierra is seated long in a .223 cartridge. Figure OAL around 2.4-2.5 inches, depending on chamber and jump length. It is possible to extract a little more speed out of the "heavier" bullet than say a mag-length 77gr SMK, again my experience, but most don't get greedy. 2650-2700-fps will shoot fine groups and scores most days, for us non-AMU types.

And with a 16/AR15, the receivers mean nothing. The only parts that matter are a good, free-floated barrel, a good usable trigger, and a properly torqued trigger-nut.