IMR 8208-XBR and the Grendel

[bwaites]

Wolf primers have a great reputation, and are used by many top competitiors. I strongly suspect that the issue isn't the primers, unless they somehow were contaminated during the loading process.

[Darkop]

They are small rifle magnums. I believe it a jp trigger. I thought it was a soft trigger but even tried them right away in a friends Grendel with a Timney trigger as he said the same thing, but they still wouldnt fire.

Does the JP hammer spring have a yellow paint mark on it. If so that is their "reduced" spring for a light trigger. I suggest a GI spec spring and I'm sure your problem will be eliminated. If not then measure firing pin protrusion with a gauge.

Until that day,
Darkop

[Tim Davis]

Darkop, yes the spring is painted yellow.

[Darkop]

Darkop, yes the spring is painted yellow.

Yep, those are very light springs. Replace with a mil-spec spring and I doubt you'll have any more problems.

until that day,
Darkop

[sneaky one]

Wow, this 8208 thread got lost.

[rasp65]

Sneaky Hold up your light and guide them back.

[stokesrj]

Well, let's bring it back around, anyone using really light bullets with IMR8208XBR? I notice the Hodgdon load data only goes as low as 95 grain Hornady V-Max bullets and doesn't have any data for bullets like the Sierra 85 grain Varmint bullet. I'm not sure why this is because the powder works well with light bullets. I've been using 81.5 grain Cauterucio Bench Rest bullets over 31.6 grains of 8208. With this load out of a 24" Krieger barrel, I'm getting around 3,200 FPS with small SD and ES numbers. Group size has been from 0.15" to 0.25" for five shot groups. Any one else using light bullets with this powder for the Grendel?

I would also suggest that this powder helped me win an Any/Any prone match. The theory is that because it is so stable over temperature I was able to squeak out a win over a very hard holder using ball powder when the temperatures dropped to 35 degrees. I know that the competitor had performed a ladder test and selected a load that was in a sweet spot that was very tolerant of charge weight variance but must not have been tolerant enough of temp changes, or so it seems. Here is a pic of a target I shot with this powder the previous month and did not win, keep in mind this is at 100 yards, prone, from a sling, no rest or bipod.

[Darkop]

Wow, this 8208 thread got lost.

Ooops, sorry on the spring thing.

8208XBR content:
I like 28.1 IMR 8208XBR With a 123 Lapua Scenar @ 2.240" COL. Lapua/AA brass gives me 2556 fps, 19.5" Shilen Results .5"-.75" groups.

Until that day,
Darkop

[sneaky one]

Rasp, I held it up , and 2 Bob's found it! Let's relight this one for a bit. Stokes, Iv'e used the 8208 all the way down to some tweaked 87-old school speer units, cut to 74-only for a future coyote load, hit 3,000 easily with a 20",-no case room left to go higher. Also used it with an 85 grn. GMX, to be used in ultra close range deer hunts. Minimal accuracy tests on either, noticed tho the speeds are identical with x-term in the lighter units. I'll be working on accuracy with those again, and a few heavier hunting bullets this spring-summer, with the 8208. The clean burn is great too. I read the chem. makeup is close to Varget,,, and maybe from ( before my time)--Thunderbird.?

[adamjp]

Rasp, I held it up , and 2 Bob's found it! Let's relight this one for a bit. Stokes, Iv'e used the 8208 all the way down to some tweaked 87-old school speer units, cut to 74-only for a future coyote load, hit 3,000 easily with a 20",-no case room left to go higher. Also used it with an 85 grn. GMX, to be used in ultra close range deer hunts. Minimal accuracy tests on either, noticed tho the speeds are identical with x-term in the lighter units. I'll be working on accuracy with those again, and a few heavier hunting bullets this spring-summer, with the 8208. The clean burn is great too. I read the chem. makeup is close to Varget,,, and maybe from ( before my time)--Thunderbird.?

I spoke with a somewhat senior gent at the Thales Mulwala facility just last week about 8208 (and why I can't get it here in Australia). IMR 8208XBR was developed as part of a new generation of powders produced by Thales Australia for the Australian Military. Thales operates the explosives and ammunition plants on behalf of the Australian government. The intent was to make powders that were even more temperature stable, increased energy (therefore velocity) and were easier for the loading plant to meter accurately. This is why it was available when the request came through. I don't know, but I suspet that 8208 is what the new ADF 5.56 round is loaded with.

Powders like H4350/Varget/H4895/H322 are the older generation I know as AR2209/AR2208/AR2206H/AR2219.

At the moment my BOLT ACTION GRENDEL is clocking just under 3000fps with a 100gn NBT using Benchmark 1, a powder not available in the US but with a burn rate roughly equivalent to VV133.

I look forward to hearing about some good loads using 8208 as I might just be able to get my hands on some soon ;-)

This may be of use to some.

http://bulletin.accurateshooter.com/2010/12/hodgdon-equivalents-for-adi-product-codes/

[sneaky one]

adam, great info- thank you. Welcome to the horde, by the way. It's great to hear from people all over the globe-that also enjoy the Grendel round. Do you hunt with it, also- which barrel length is your bolty? Who made your rifle would be of interest to a few hundred on here also ! I have some load data for the -previous, and the 110 grn. units.

[txgunner00]

Great info in here. I've been happy enough with it that I just picked up another 8lbs of it.

As stokesrj said, 8208 is not completely insensitive to temperature. I was using a load of 28.6 gr behind a 123 smk until I shot them on an extremely hot 115 deg day and in the sun. I had a few pieces of brass start to pull apart so I backed down to the next sweet spot of 28.3. No problems since.

It's given me several 6" groups at 1K and this one.

gren 1000.jpg

[RangerRick]

Well, let's bring it back around, anyone using really light bullets with IMR8208XBR? I notice the Hodgdon load data only goes as low as 95 grain Hornady V-Max bullets and doesn't have any data for bullets like the Sierra 85 grain Varmint bullet. I'm not sure why this is because the powder works well with light bullets. I've been using 81.5 grain Cauterucio Bench Rest bullets over 31.6 grains of 8208. With this load out of a 24" Krieger barrel, I'm getting around 3,200 FPS with small SD and ES numbers. Group size has been from 0.15" to 0.25" for five shot groups. Any one else using light bullets with this powder for the Grendel?

I would also suggest that this powder helped me win an Any/Any prone match. The theory is that because it is so stable over temperature I was able to squeak out a win over a very hard holder using ball powder when the temperatures dropped to 35 degrees. I know that the competitor had performed a ladder test and selected a load that was in a sweet spot that was very tolerant of charge weight variance but must not have been tolerant enough of temp changes, or so it seems. Here is a pic of a target I shot with this powder the previous month and did not win, keep in mind this is at 100 yards, prone, from a sling, no rest or bipod.

Where to buy the 81.5 grain Cauterucio Bench Rest bullets?

Thanks!

RR

[stokesrj]

Robert (Bob) Cauterucio
482 Comerwood Ct.
South San Francisco CA 94080-4205
650-583-1550
They are not a regular production item so it may take a wile and he may require a large quantity, I think I had to buy 1,000 but can't remember for sure.
Bob

[txgunner00]

Robert (Bob) Cauterucio
482 Comerwood Ct.
South San Francisco CA 94080-4205
650-583-1550
They are not a regular production item so it may take a wile and he may require a large quantity, I think I had to buy 1,000 but can't remember for sure.

Bob

How does he get the weight down? Are they just shorter or do they have a deep open cavity?