Help with 8208 & 75 Amax load work please.

[Trevor300wsm]

Hey guys,

I'm having some trouble getting a load using 8208 & 75gr Amaxs in my .223. I typically never have any issues finding a load for any of my rifles, but this one is giving me a hard time. I already have a great load for this same rifle using Varget and 75 Amaxs, but I have 10lbs of 8208 and would like to use it if possible. Here is where I am so far.
Stiller Tac 30
Bartlien 1:8tw at 22"
8208 xbr
Lapau brass
CCI 450's
75 Amaxs

I started at 24gr and went up in .2gr increments. I found a load at 24.8 that produced .25moa accuracy at 100yds, but the ES & SD were way too high (using a magnetospeed that I've used many many times before). I took this 24.8 load and played with the seating depth. Started at 1.960 (base to ogive) and went down in .005" increments down to 1.940". The chronograph numbers stayed way too high and the accuracy wasn't getting any better. I went back to charge weight and made my way up to 25.3-25.5 where I found a really good node with "one hole group" loads at 100yds. BUT, the chronograph numbers were still not where they should be. ES was 30-50 fps and SD was 15+fps. This is unacceptable for me. I like to have both in the single digits, especially SD.

So....what should I do? Continue to go up in charge weight? Try going longer with seating depth? Going shorter again with this higher charge weight? I figured I would have pressure issues with 25+ grains, but I'm still not seeing any signs of pressure on the brass and bolt lift is not showing anything either.

Edit: if anyone is wondering why the ES/SD matters so much to me, this is my practice rifle during the offseason. It'll get shot out to 1K pretty frequently. The velocities need to be consistent.

Any help would be appreciated.
Thanks

 

[snert]

try a different primer, keep everything else the same. I have been happy with standard match Federal primers, but every load is different. I use that powder in 222 and in 6BR but not with heavy for caliber bullets. 50 in the 222 and 70 in the BR, FWIW.

snert

 

[rmist]

+1 above...try CCI 400's for your primer.
Seems like almost everyone you discuss the 223 has the same issues with high SD and ES. Mine has higher numbers than I like as well, but it shoots very well. Maybe drop down to a slower accuracy load for your rifle. Possibly practice at 600 yds. Just as challenging !!!

 

[expiper]

Trev,,,it sounds to me that you have found what we all are looking for (1/4" accuracy) ,,,throw away the chrono and shoot some 300-500yd targets ,,,they will tell the tale,,Roger

 

[rminut]

well this will probably go over like a fart in church because you are going to shoot what you want but I feel compelled to add my two cents for the shooters next to you. You didn't list a bunch of parameters, like o.a.l and chamber, that can add up to make a huge difference but the IMR book lists 22.7gr as max for a 75 grain JLK bullet. You are starting at 24 and moved well above that. I don't care what the brass looks like but you are far overpressure and that is why the SD/ES numbers are terrible.
Just so you know Quickload shows 25.5gr at 2.48"o.a.l. shows a pressure of 77Kpsi! I know there are a lot of unknown factors here but no matter how many small changes you make to that load it is far overpressure and unsafe. I don't care how well it shoots, something will fail eventually at that psi.
I shot a lot of 80gr amaxs in 223Rem and can tell you that the Amax design makes a lot more pressure than other 80gr bullets. They have more bearing surface than comparable weight bullets. You should probably start around 23gr max and not move much over that. Everyone I know that has a Wylde chamber has set Amax's .020" off the lands and it's worked great.
What you gain at 25.5gr in speed will not be much change on a target except maybe after 1k yards. It's not worth the overpressure condition. sorry to be the messenger of overpressure news.

 

[shoot4fun]

I tried 8208XBR in my 26" 223 Kreiger and was disappointed. Not disappointed in the accuracy but in the load's ability at 1000 yards. I was using 77SMK and the load was great out to around 800 before it just fell apart. I was in the same spot as you; a lot of 8208 and nothing to use it for until I found it shot great in my 6BR with 107SMK. I just don't think you'll ever get the velocity/SD combo you need for shooting 1000 yards with it in 223 case volume. I found 8208 to be a funky powder. While I can go well above published data in some calibers (6BTR for one) I can't in others. Plus, an experiment in my 7MM08 with 162 Amax showed me 8208 can generate a lot of pressure without it showing the signs we usually look for. I lost primer pockets in 7MM08 Lapua in one loading at 41.3 without any extractor marks, flat primer, blown primer, etc.

 

[rminut]

you are not the first i've heard go from no signs to blowing primers or worse with this powder and heavy for the caliber bullets. The powder will shoot heavy bullets, but it seems everybody tries to get velocity with them and gets into trouble. A poster on here stated he had a case separation in .308 with new brass and 155's, no signs to case separation! That is peaky and scary stuff.
The powder is simply too fast to get velocity with heavy bullets. Slower powders are made for that and for good reason.

 

[snert]

you are not the first i've heard go from no signs to blowing primers or worse with this powder and heavy for the caliber bullets. The powder will shoot heavy bullets, but it seems everybody tries to get velocity with them and gets into trouble. A poster on here stated he had a case separation in .308 with new brass and 155's, no signs to case separation! That is peaky and scary stuff.
The powder is simply too fast to get velocity with heavy bullets. Slower powders are made for that and for good reason.

+1 on that. Just cause you have the parts doesn't mean they fit together!

 

[DIBBS]

I know this topic is from a while ago, any new data on the amax eld-m and 8208xbr combination in a .223? Thanks!

 

[jbpmidas]

I’ve had good luck with 75 Amax and 24.5 8208. 2990 is my velocity. I load it on a Dillon 550, so my ES/SD is a little higher than I’d like. It will group well under 1/2”, with an occasional flyer I attribute to the powder thrower. For PRS practice or short matches, it’s great fun! My barrel is a 1:8, 26” Bartlein.

 

[DIBBS]

I’ve had good luck with 75 Amax and 24.5 8208. 2990 is my velocity. I load it on a Dillon 550, so my ES/SD is a little higher than I’d like. It will group well under 1/2”, My barrel is a 1:8, 26” Bartlein.

Thanks, much appreciated. The test loads ladders I have loaded thus far only go up to 23.9 gr 8208, with the AMax/ELDm. I am trying Fed 205's and Rem 7 1/2's so far. Hope to get to the range today or tomorrow.

 

[Fast14riot]

23.2 with a 75hpbt and a rem 7 1/2 is my service rifle load.

 

[Depart123]

I only have experience with 8208 in 223 with 62 and 68 and 69 grainers, but here is what I found:

8208 shoots like crap right up until it doesn't. My regular regimen has become to start 1.5 grains below max and shoot 10 round strings at 0.3g increments until the SD's tighten up. It will go from SD's of 20-26fps to single digits as soon as it reaches optimal pressure. You might get one more increment of single digit SD's before it falls apart again. I've never seen the node larger than that. It could happen, I just haven't seen it.

Now whether or not that node is at an optimal point in your barrel timing, that is another thing all together.

 

[Michael C]

A slightly different setup in a AR service rifle, but I shoot 23.2g 8208 in a 1-7 20” with 77smk and 80.5 Berger. It shoots extremely well, groups small and is capable of shooting clean at 600. My point is you may find starting lower at 23 yields a better result.

 

[Huckleberry75]

I only have experience with 8208 in 223 with 62 and 68 and 69 grainers, but here is what I found:

8208 shoots like crap right up until it doesn't. My regular regimen has become to start 1.5 grains below max and shoot 10 round strings at 0.3g increments until the SD's tighten up. It will go from SD's of 20-26fps to single digits as soon as it reaches optimal pressure. You might get one more increment of single digit SD's before it falls apart again. I've never seen the node larger than that. It could happen, I just haven't seen it.

Now whether or not that node is at an optimal point in your barrel timing, that is another thing all together.

Where did you settle on it with the 62gn class of bullets? T.i.a.
Huck

 

[Depart123]

Where did you settle on it with the 62gn class of bullets? T.i.a.
Huck

I wouldn't say I've settled on a load with this powder and 62's. Honestly, it grouped like rat shit in a dresser drawer (3+MOA @200yds), but I was using milsurp SS109's. I'm not sure these bullets would do better with ANY powder. However, with the bullet weights I've tried, this powder tightens up in respect to velocities right at max charge (5.56 loads 62K PSI). That is between 23.5g & 23.9g in my rifles.

Side note: I just shot some of this yesterday with 69's, Fed brass, CCI 400. 23.9g. I shot a total of 50 rounds at a single target w/single point of aim, 10 round strings. Single loading from the magazine put 20 rounds in 1 MOA @ 200 YDS. Firing from a loaded mag with no other changes (20rnd mag w/10rnds loaded), still 10 round strings, opened the group up to 2 MOA. 50 rounds from a semi auto in 2 moa isn't bad in my opinion, but it is still a fairly drastic difference.

 

[Huckleberry75]

I wouldn't say I've settled on a load with this powder and 62's. Honestly, it grouped like rat shit in a dresser drawer (3+MOA @200yds), but I was using milsurp SS109's. I'm not sure these bullets would do better with ANY powder. However, with the bullet weights I've tried, this powder tightens up in respect to velocities right at max charge (5.56 loads 62K PSI). That is between 23.5g & 23.9g in my rifles.

Side note: I just shot some of this yesterday with 69's, Fed brass, CCI 400. 23.9g. I shot a total of 50 rounds at a single target w/single point of aim, 10 round strings. Single loading from the magazine put 20 rounds in 1 MOA @ 200 YDS. Firing from a loaded mag with no other changes (20rnd mag w/10rnds loaded), still 10 round strings, opened the group up to 2 MOA. 50 rounds from a semi auto in 2 moa isn't bad in my opinion, but it is still a fairly drastic difference.

I wonder if a light crimp might help stabilize some of this growth in the group when fed from the mag? Maybe getting pushed back a little into the case with feeding?

 

[Depart123]

I wonder if a light crimp might help stabilize some of this growth in the group when fed from the mag? Maybe getting pushed back a little into the case with feeding?

I've consulted people with a lot more experience than I on the problem. What they have told me is that 1) it is a common problem and 2) it has to do with spring pressure from the magazine dragging on the bolt, which gives variances in bolt lock up. Just one more reason of why I will never be a semi auto fan.

 

[kevinbritvec]

Hey guys,

I'm having some trouble getting a load using 8208 & 75gr Amaxs in my .223. I typically never have any issues finding a load for any of my rifles, but this one is giving me a hard time. I already have a great load for this same rifle using Varget and 75 Amaxs, but I have 10lbs of 8208 and would like to use it if possible. Here is where I am so far.
Stiller Tac 30
Bartlien 1:8tw at 22"
8208 xbr
Lapau brass
CCI 450's
75 Amaxs

I started at 24gr and went up in .2gr increments. I found a load at 24.8 that produced .25moa accuracy at 100yds, but the ES & SD were way too high (using a magnetospeed that I've used many many times before). I took this 24.8 load and played with the seating depth. Started at 1.960 (base to ogive) and went down in .005" increments down to 1.940". The chronograph numbers stayed way too high and the accuracy wasn't getting any better. I went back to charge weight and made my way up to 25.3-25.5 where I found a really good node with "one hole group" loads at 100yds. BUT, the chronograph numbers were still not where they should be. ES was 30-50 fps and SD was 15+fps. This is unacceptable for me. I like to have both in the single digits, especially SD.

So....what should I do? Continue to go up in charge weight? Try going longer with seating depth? Going shorter again with this higher charge weight? I figured I would have pressure issues with 25+ grains, but I'm still not seeing any signs of pressure on the brass and bolt lift is not showing anything either.

Edit: if anyone is wondering why the ES/SD matters so much to me, this is my practice rifle during the offseason. It'll get shot out to 1K pretty frequently. The velocities need to be consistent.

Any help would be appreciated.
Thanks

 

[kevinbritvec]

75 grain A-Max bullets are not designed for or intended for use at magazine length. Start around .020" jump to rifling and work closer and further away until you find good accuracy.

Your load is too hot! Way too hot. Look at 23.5 grains of IMR-8208-XBR as a possible maximum and that may be too hot.

If you have a chronograph use it. I'm surprised you haven't pierced or blown primers.