More then max load?

[Prc329]

Is it safe to go higher then the max load listed for a specific bullet?
Just curious. The data on H335 behind a 77g bullet should hit 2700fps but I was wondering if after I chrono in my guns and if it does not get where I want it would be it safe to add more powder or should I just switch to something else? I plan on using LC brass I got from Top Brass as well as CCI BR4 primers. I am developing for an 18" SPR profile stainless steel barrel and will also be using it in a Mark 12 Mod 0 or 1 upper I have planned for my Calguns lower as well as a RRA NM upper I own.

[PistolPete75]

sounds dangerous to me, i would go with a different powder if your not happy with your velocity.

[Jicko]

What chamber do you have? Mk12 Mod 0/1 have AMU chamber. And Wylde and 5.56 NATO chamber can take higher than databook SAMMI 223REM pressure. So what chamber do you have is the most important info.

And then, when you are going HOT, you need to develop your rounds by working your way up. And testing them and looking for overpressure signs.

So, where do you live? Maybe we can go work on our rounds together in Rainbow Range or Pala Range near Temecula.

[Jicko]

sounds dangerous to me, i would go with a different powder if your not happy with your velocity.

Using a different powder won't help if you want to get to Mk262 velocity. Mk262 Mod1 velocity ~ 2750+ fps, it needs more powder than ANY databook will give you (as they are listing for 223 REM), and it is probably unsafe in 223 REM chambered gun.

[Franksremote]

A number of things play into not reaching published data:
1) All reload manuals are different, one says one thing, the other says another; safest way is to start 10% below and adjust accordingly.
2) Watch for pressure signs as you increase the charge. Flattened primers, separated headcases, splits
3) Play with crimp a little, a little tigher will increase fps
4) Pay attention to #2
5) Seat the bullet a little deeper; less case volume, bigger bang.
6 Pay attention to #2

Thsi is if you want to stick to the same powder. If not, try something else

[Prc329]

My guns are wylde chambered. The Mark 12 mod 0/1 I am looking at is Adco built and will have a wylde chamber if I recall. I'm in Long Beach but do get to SD a lot. Next time I am planning a trip I'll let you know so we can set a time and date.

[ocabj]

The AR action can handle quite a bit of pressure. It's not because of the Wylde chamber (or NATO) necessarily. It's simply the design.

The weakness is going to be the cartridge case. When I was experimenting and found a load to duplicate MK262, I found the fired cases would every now and then result in popped primers and pretty much all of the cases had enlarged primer pockets.

If you load ammo for MK262 specs, I would suggest you chuck the brass after a couple firings. I think the brass life, even with LC brass, is going to quite short with the kind of pressures from the resulting MK262 specs.

[Jicko]

By the way, it may NOT be needed for 77grainers to get all the way to MK262 speed for them to be accurate and be able to reach long ranges. And on the whole, that may be a better load than just blindly push them faster and faster..... faster may not necessarily be better....

[Fjold]

You can go as high in pressure as your face can take when the brass let's go. For primers to blow out, etc. you're talking about pressures in excess of 75,000 PSI

Most of the velocities for milsurp ammunition is based on the performance in 20" barrels, if you're shooting an 18" barrel you can't make up for that 100-120 fps you lose with the shorter barrel.

[Jicko]

You can go as high in pressure as your face can take when the brass let's go. For primers to blow out, etc. you're talking about pressures in excess of 75,000 PSI

Most of the velocities for milsurp ammunition is based on the performance in 20" barrels, if you're shooting an 18" barrel you can't make up for that 100-120 fps you lose with the shorter barrel.

But I guess, most of us, are trying to get to Mk262 Mod1 performance on the rifle which it is tested on. ie. Mk262 Mod1 on 18" Mark 12 SPRs. The general consensus is that the Mk262 round is going at about 2780 +/-15fps on particularly 18" SPR barrels.

http://www.calguns.net/calgunforum/showthread.php?t=54716

[Prc329]

By the way, it may NOT be needed for 77grainers to get all the way to MK262 speed for them to be accurate and be able to reach long ranges. And on the whole, that may be a better load than just blindly push them faster and faster..... faster may not necessarily be better....

I feel ya. I have so far learned (still need to test it) that 308 does better slower, well at least that is what I have read. I still need to try it out on my own. I just figured the military uses the MK262 running over 2700 fps in an SPR rifle. That is the idea behind the rifle I plan on developing it for as well as I will use it in a 20" barrel.

Looks like I have the perfect excuse to go to Angeles as much as possible. I also finally got my wife to warm up to the idea of shooting my AR. I may need a load that will cycle the bolt and be a little lighter or just use up my AE.

[Jicko]

I feel ya. I have so far learned (still need to test it) that 308 does better slower, well at least that is what I have read. I still need to try it out on my own. I just figured the military uses the MK262 running over 2700 fps in an SPR rifle. That is the idea behind the rifle I plan on developing it for as well as I will use it in a 20" barrel.

Looks like I have the perfect excuse to go to Angeles as much as possible. I also finally got my wife to warm up to the idea of shooting my AR. I may need a load that will cycle the bolt and be a little lighter or just use up my AE.

Regarding the MK262-like load, our goal is very similar. How after do you live from Temecula?

As for your wife, just have her shoot the AE223 and gather up those cases for you to make your MK262 rounds by the way, I think she may enjoy a 24" varmint setup more.... if you shoot AE223 out of such a setup, it almost felt like a suppressed rifle, barely any recoil or muzzle lift, and almost sounded less noisy....

[Prc329]

I have a RRA National match gun that I may let her try out. I have also been looking for an excuse to buy a 22 . Maybe I'll get a 10/22 and take her to the pistol range and shoot some steel. Oh and I live in Long Beach. A little over 1 hour. I do go to San Diego a lot. Not as much since I have the two little ones but I do go down a lot. We gotta get together at Pala one time. Can you shoot there without being in a match?