Imr xbr 8208

I bought some of this last year mostly for use in a 6 BR bolt gun, but people have claimed that this powder is quite good in an AR-15 .223. A very reliable person I know personally - among others - has said so, but when I loaded 23.2 or 23.4 grains in a Winchester case and the 77 grain Sierra, I have experienced cycling problems (not every time) In slow fire, the bolt will fail to go all the way back. In a rapid fire string it has not jammed, however. The barrel is a Wilson 26 inch with a Bill Wylde chamber. IMR gives 23.2 as a max load with the 77 grain bullet. Are there any of you who have experience with 8208?
Thanks, John

today's results

I loaded some 77 grain Sierra loads with 23.6 & 23.8 grains of XBR 8208 and the bolt did not lock back. The primers showed no real pressure signs.

By contrast, I shot some H4895 loads (23.0 grains) and the gun functioned perfectly. The same for a RE-15 load with 24.0 grains.

I just am looking for an answer why this happens. Others on different forums don't have the experience that I am having.

I may be onto something. Today I loaded some test loads with 23.1 grains - on the weaker side - and some heavier stuff. Before I shot, I lubed the clean bolt & carrier with the home made "red death" lube and the gun cycled fine. Maybe something simple as that?...

Most people I have read about this on other forums as well as some this one shoot 23.2 grains. Thanks for any suggestions.

John

Thank you Scott. I spoke with a barrel maker in Portland and he thought perhaps the high pressure loads could possibly have expanded the case enough to impede cycling. He said I should try keeping the bolt wet with LSA, his personal choice. John ought to know.

This is a Wylde chamber in a Wilson match barrel. I have had cycling problems with high end loads - 23.9 grains as well as 23.1 grains, all the while the RE-15, (24 grains) H4895 (23 grains)& Varget (24 grains)had no problems at all. I have not looked for scuff marks, But I will. What is odd is that when I practice with rapid fire strings - 2 & 8 round loadings, there hasn't been a jam, only in single loading. As I wrote, once I lubed the bolt & bolt carrier it began to function even with 23.1 grains. The trouble with testing is that it eats up components which as you all know are difficult to replace at this time.

This powder gives my the most accurate groups off the bench at 100 yards.(the only local range I have) I really want to shoot this in Phoenix next month.
The barrel is fairly new with only a match or two shot with it. Less than 500 rounds through it.

Thanks to all of you. (I am not alone with 8208 cycling problems)

John - Albany, Oregon

Good morning Pop,
The cycling was with a Bobsled as well as a 20 round GI magazine. Your point is well taken, but this stuff was what I used with the other non 8208 loads and there was no problem. In the past, I have had worn boltstops and crummy magazines, but not this time.

The lube I used is the formula the national guard team was using. I also have some LSA to use. Grease seems to pick up grit - at least the stuff I tried to use years ago did. I have not tried Mobil 1.

To give you another hint : I am a full blooded Swede (stubborn) with a lot of years behind me.

Well, what troubled me from the beginning is what I read from several reliable competitors who reported the same load - 77 grain Sierra & 23.2grains - give or take a tenth of a grain, and suffered no malfuntions. Same bullets, same chamber. One shooter suggested that a CLE chamber would require slightly lower charges.

You realize that there are different .223/5.56 chambers out there.

It does not matter if Krieger makes your barrels or anyone else. There are a handful of different chamber dimensions that every barrel maker uses. Krieger uses a pattern that is available - I sincerely doubt that krieger invented their own. There are chamber standards - otherwise there would be chaos for reloaders.

Are you saying that Krieger sent a chambered barrel direct to you? All the Kriegers I have seen including my 6mm, came from them as a blank and the gunsmith chambered it.

I solved the cycling problem today. After speaking to a local high power competitor I know, I took his advise and really lubed the bolt/carrier with the 'red death" oil and the gun functioned perfectly with the 23.2 grain load. So now, all is good - for the moment...