imr 8208-xbr info

[spclark]

What sort of loads (including starting load) are you using in your 6XC, I'm curious?

With all appropriate caveats, I kind of fell onto the load I ended up using. When I started there were few sources for load info as the stuff was too new so I interpolated a start load of 37.0 grains for 105-weight bullets from two cartridges that had info published. Also made some at 38.0 and 39.0.

Shooting the 37.0 produced results @ 600 that astonished me, beating the other four propellants I was testing that day. Firing two of the 38.0 grain loads gave me sticky bolt lift and no improvement in accuracy but fully 50 fps more velocity and SD < 8.

I never fired the 39.0 loads, they got broken down when I got home.

This was using home-hBN coated Berger 105VLD bullets with Wolf KVB-7 primers in the then new Tubb-sourced Norma 6XC cases. Quadlite action, Bartlein 30" 1:7.8 barrel put together for me by Carl Bernosky in 2008 using a new 6XC reamer he'd just gotten from Hugh Henriksen.

I've since backed off to 36.7 grains as the 37.0 charge at elevated temps (90+) blew a couple of primers out in 2010.

DO start with reduced loads in YOUR equipment under YOUR conditions please. From all reports and my experience with this propellant pressure builds rapidly & owing to its density it's easy to think a little more won't hurt when in fact you may be wrong letting that thought cross your mind.

 

[Raptor]

Anyone tried it in the 260??? Thanks!!

 

[lpreddick]

i have been under the assumption that we NEVER mix powders, period!!! i mistakenly mixed ball and stick powder and trashed some brass, the gun saved my face/hands, so i'm very suspicious when i read of competemt shooters purposedly mixing . there is a thread on another site discusing a 50/50 mixing of H322 and IMR8208XBR and using it in the 6 PPC with 68 gr bullets getting 3300+ fps. there was a military surplus 8208 slightly faster than the current IMR 8208XBR but slower than H322 and i suspect this blend is close to it's burn rate and performance. anybody have any input. i have some of the military surplus 8208 and it shoots fantastic in my 6BR with 64-66 gr bullets. can this mix be a replacement when i run out? i remain hesitant to mix.

 

[amlevin]

i have been under the assumption that we NEVER mix powders, period!!! i mistakenly mixed ball and stick powder and trashed some brass, the gun saved my face/hands, so i'm very suspicious when i read of competemt shooters purposedly mixing . there is a thread on another site discusing a 50/50 mixing of H322 and IMR8208XBR and using it in the 6 PPC with 68 gr bullets getting 3300+ fps. there was a military surplus 8208 slightly faster than the current IMR 8208XBR but slower than H322 and i suspect this blend is close to it's burn rate and performance. anybody have any input. i have some of the military surplus 8208 and it shoots fantastic in my 6BR with 64-66 gr bullets. can this mix be a replacement when i run out? i remain hesitant to mix.

My concern with "mixing" is that of consistency in the mixed product. How do you know that each of he powders are mixed consistently in your bulk container.

If one was to "mix" powders for a particular load I think it would be OK if they metered out a specific amount of each powder, mixed it well, then poured the combined charge into the case. At least that way you wouldn't end up with some cartridges being charged with uneven mixes, getting more of one powder than desired at various times.

 

[Nalgi]

I cant complain...

 

[Joe R]

That's pretty sweet Nalgi.

Regarding mixing powder, I think that's crazy stuff.

 

[skiutah02]

I've had excellent performance in both 308 and 223. Initially used to develop a load for a 155 SMK. Since Dec have used over 8 lbs. and over 1000 rounds. Can get near 3030 fps with mild pressure signs, ES under 15 and SD of 5. Shot at several 600 matches and one 1000 yd (FTR) with good success (shooter limited).

Used it to develop loads for 68, 75 and 77 gr loads in 223. Saw about 100 fps INCREASE in velocity vs. varget at same weight loads with same or better accuracy and no pressure signs (please work up loads on your own). The 68 gr Horn HPBT was over 2950 fps, 75 at 2750 fps and 77 SMK was 2725 fps from a 20 in AR, VEX-SS. Could not get lower than 20-25 fps es in 223 consistently, but they were lower than with varget. Little to no temp sensitivity. Loads developed near 0oF were within 20 fps at 70 oF.

IMHO a great powder worth trying in 223 and 308 (but please leave some for me ) Drew

 

[Jeff A]

8208XBR is the powder of choice for my 6.5 Grendel AR. Been getting 1/2 MOA to at least 200 yards.

 

[timeout]

I cant complain...

That is disgusting. Makes me wonder why I have thousands invested in custom builds? This will create a run on Ruger Americans and subsequently hoarding and shortages!!! ;D ;D

 

[Joe R]

That is disgusting. Makes me wonder why I have thousands invested in custom builds? This will create a run on Ruger Americans and subsequently hoarding and shortages!!! ;D ;D

Yea,
That reminds me that when my daughter was taking violin lessons, the violin sounded like two cats fighting. But when her teacher played it, it made music.

Joe

 

[jwink]

It is my only powder that I load in .22-250, amazing stuff, first group shot was half the size of anything I had done before. Now have an honest 1/3 MOA Rem 700.

 

[skiutah02]

Here is the first OCW I ran this winter with XBR 8208 and the 155 SMK Palma from a Savage FTR in 308 (1 in 12). It was 12oC that day, I ended up going to a higher node than 44.0, but I was excited to see the potential. Drew

 

[MildBill]

It is my only powder that I load in .22-250, amazing stuff, first group shot was half the size of anything I had done before. Now have an honest 1/3 MOA Rem 700.

what bullet & primer are you running?

I tried a work up series with it in my 22-250 with 55 grain sierra 1360's lit by Fed 210 match primers and it was not a positive outcome.

 

[TAJ45]

I bought a used Lilja 20 BR chambering and previous BR shooting owner sent me data for the 55 Bergers and 8208XBR. I snagged 8# of it from Wideners.

As mentioned previously, my club's serious LR shooters are touting the 2000MR as giving extra velocity w/o pressure signs.