Home Forums Reloading Varmint Rifles 8208 XBR vs. Benchmark in the 223

Awhile back I picked up some 8208 XBR on a whim when it was brought up as a powder for the 223. The BR guys around here panned it but being the curious type I had to try it. So here goes.

Test subject load - 25.0 grains 8208XBR, 52 SMK, once fired RP brass, Federal Gold Medal Primer.

Load 2 - 25 grains Benchmark, 52 SMK, RP once fired brass from same lot as above, Federal GM primer. (this is a known load for velocity from both rifles)

Brass prep was FL sized w/ shoulder bump .002, trimmed to 1.750 as I was going to use 2 rifles. (didn't want variance due to brass being mated to 1 rifle chamber)

Rifles used were both Cooper Mod. 21 MV 24" barrel, exact copies except 1 is a 14 Twist and 1 is 12 Twist.

Seating depth for all rounds 2.195

25 grains of 8208 is .4 off of max for that bullet, 25 grains of Benchmark is 1 grain off max according to hodgdon.

Temp was 39 degrees with a 10 - 4 o'clock variable wind at 10 to 15 mph with gusts to 23 but this was shot for velocity not group as the rounds were not optimum for either rifle to shoot for group. All strings were 10 shots fired 1 shot per minute. The rifles were allowed to sit for 30 min and no cleaning between strings. Barrels were still dirty from last outing.

String 1 8208 out of a 12 twist Avg. velocity 3203
String 2 8208 out of a 14 twist Avg. Velocity 3176
String 3 8208 out of a 12 twist Avg. velocity 3168
String 4 8208 out of a 14 twist Avg. Velocity 3158
String 5 Benchmark out of a 12 twist Avg. Velocity 3389
String 6 Benchmark out of a 14 twist Avg. Velocity 3398

The difference between 2 strings of 8208 was 35 FPS/ avg. 3185 from the 12 twist. 204 FPS slower than the known Benchmark load of 3389.
The difference between 2 strings of 8208 was 18 FPS/ avg. 3167 from the 14 Twist and 221 FPS slower than a known Benchmark load of 3398.

So conclusion on my limited test sample of 8208 XBR (max load pressure 53,400 psi) is that it creates more pressure/recoil, and less velocity for the powder charge than Benchmark (max load pressure 49,800 cup). The recoil difference was obvious while firing.
Velocity variations between high and low per string were pretty much even. So no advantage there between the 2.
Accuracy was tilted slightly to benchmark as it turned in 4 5 shot clusters (.5 in) or better compared to only 2 with the 8208

I don't think that 8208 XBR is going to make the cut, same powder charge, more recoil, less velocity, and no better accuracy. Next time out I am going to use match brass formed to the rifles in question and use 20 rounds in each rifle of 8208, 20 rounds each Benchmark, and throw in 20 rounds each of H-335 (another known velocity load)and see how that compares.

Good stuff Swifty,

Keep us posted.......

Interesting, I just bought a pound to try, but look forward to your results!

I had a real nice load in my CZ 527 varmint kevlar with 60gr vmax bullets and 23gr of Benchmark, best groups I ever got. G

Going to have a nice day tomorrow. 70 for the high, winds 5-8 mph. perfect day to sit at the bench, run the chrony, and shoot for group.
Just finished up all the loads I wanted to test. Powders are 8208 XBR, H-335, and Benchmark.
Bullet is a 52 SMK. Primer I switched up to a BR4 instead of Federal GM. All brass is match proven and prepped.

Trim length 1.7525 ~ .0005 inside/outside chamfered exactly alike. This step is done while trimming.

All powder charges are 25.5 grs. 50 rounds each.

Seating depths are 2.1895 ~ .0005 Base to Tip. Ogive 1.8455 ~ .0005

Brass line up is:

Benchmark in Norma
H-335 in Nosler
8208 XBR in Lapooey

Test rifles are the same. Cooper M21 MV 223, both have Loopy VXII 6.5 x 18 AO w/target turrets and fine varmint plex. So we will see how the groups and velocities pan out.

The day was great, will put up a result when I get all of the data sorted out. Had a couple of surprises too.

Finally got all of my data sorted out so here goes.

Got everything set up and fired a test string from each rifle using rounds left over from the previous test. Temp was 56 deg. 37% humidity, Bar. Press. 29.82 and falling.

8208 14 Twist = 3138 Fps.

Benchmark 14 Twist = 3344 Fps

8208 12 Twist = 3151 Fps.

BM 12 Twist = 3373 Fps.


Temp at the time of the strings was 66 deg. 37% humidity, 29.81 and falling.

8208 14 Twist

String 1 = 3289
String 2 = 3298
Average = 3293
Previous = 3185
Gain = 108 Fps

8208 12 Twist

String 1 = 3302
String 2 = 3298
Average = 3300
Previous = 3389
Gain = 133 Fps

Benchmark 14 Twist

String 1 = 3427
String 2 = 3436
Average = 3431
Previous = 3389
Gain = 42 Fps

Benchmark 12 Twist

String 1 = 3439
String 2 = 3428
Average = 3433
Previous = 3398
Gain = 45 Fps

Conclusion:
I was completely surprised by the amount of gain that a primer and match brass change would give in the 8208. My reaction to the data is that Benchmark is a much better match powder than 8208 for the simple fact that it exhibited more stability in velocity over a variety of changes.

Benchmark retained basically the same velocity even though brass, primer, an powder charge was altered. Norma is known for being a little more generous in case capacity, so even with a 1/2 grain increase in powder charge the change in velocity as minimal. And according to Hodgdon this was not a max load, but max book velocity was exceeded. Nosler actually has this load as 1 grain under while Hodgdon it is 1/2 grain under.

8208 unfortunately needed smaller case capacity, hotter primer, and a max load to attain its book stated velocity. Having shots that can be as much as 100 - 150 Fps different just because you used the wrong primer, or had a case capacity larger than what you used before, than it is pretty much worthless in todays market as you have no reason to believe that you will be able to get those exact components again.

In my book, Benchmark gets the nod.

Now the other surprise. Was shooting my Swift, 55 grain BK, H-380 trucking along at 3700. On the second shot of the string I get this in the lower right.



The one left of the 10 ring is shot 1(fouler) to the right are shots 3,4,& 5.
Now what would cause 1 round to keyhole, then proceed to slap 3 right together ???

The prop on my 50 yard wind flag that's what. What's the odds of a spinning prop clipping a bullet @ 3700 Fps?

More impressive is the fact that the tumbling bullet still hit the target that close to your other cluster after hitting the wind flag!

Makes me wonder how many bullet failures on deer contacted an obstruction before hitting flesh?

Benchmark is all I use for 5 .223s. Four of the rifles shoot the same load, 26.5 grains under a 50 grain V Max, 2.276" OAL, CCI 400.

Boringly accurate, 3400 ft/sec.


P

I've tried Benchmark and IMR 8208 XBR for 223 Remington loads and they didn't beat RL-15 for me. I also tried other powders with the same result.



For my 270 Winchester, I consider IMR 8208 XBR the cats meow. It also meters better than any other powder I've tried. So, I like IMR 8208 XBR but not for 223 Remington loads. Benchmark has not been my go to powder for any cartridge I've tried it for but then my emphasis is on accuracy as opposed to velocity.

Nice shooting, but I cant stand accurate rifles.

Benchmark in the 223 from one of the above test strings. I quit measuring long time ago , but guess its a little over .25 on bottom, and pulled one on the top but close



5 shots 25.06 110 AB RL22

Swiftly thanks for your hard work on this! I've been impressed w/ XBR in my 6-250 but haven't put it against Benchmark or over a chrono yet.

Can Benchmark be described as essentially an extreme version of H-335?

Not quite but it burns MUCH cleaner.

8208 may work just fine in a larger case like yours. My main problem with 8208 was the primer issue. My ES & SD's were a little on the high side around 30 & 18 I think.

Probably will be trying 8208 again soon, but I got some LT-32 the other day and want to try it out. Also found that I have some AA 2015 which you can blend with (LT-32) not 8208 (my bad) to alter the burn rate which sounds interesting. Plus the new Oehler needs to be played with.

As to Benchmark, Yes, it is an extreme that pretty much mimics 335. Hodgdon has it burn rates at 80 and 81 . Charge weights for the same weight of bullet are damn near identical and pretty much interchangeable, 1/2 grain difference between max in most manuals. It does burn a lot cleaner than 335, and it definitely doesn't care if it hot or cold, pretty much performs the same each time. Haven't noticed lot to lot variations much either which I cant say for 335.

And I still like to shoot 335, keep going back to that dirty stuff just for giggles. With Benchmark, I get mostly over book velocity for charge weight than with 335. Mileage may differ for others.

You might have gotten some mis-information about this. some people have blended LT-32 with Accurate 2015 but only the Canada manufactured 2015.
When Lou Murdica was doing the testing with this powder they were using 2015 and trying different things with different lots, when the LT-32 finally came out it was a bit faster burning than the 2015 so some benchresters tinkered with blending the two to slow it down a bit.

If your can of Accurate 2015 says Made in Czech Republic or Israel or does not state country of origin, I would not blend LT-32 with it.

Never heard of anyone blending it with IMR8208XBR

btw: Lou Murdica had a hand in making this powder also but that is another story.

I don't think ball would blend well with stick.

I fixed it, my bad. stayed up toooooo late

Copy of an email to Speedy.

The LT-32 is an exact copy of the original T-32 manufactured in the same plant and on the same machinery as the original. Lou Murdica has been extensively testing it and he tells us it is the easiest powder to tune that he has seen in 40 years. According to Lou, the chamber that everybody was using in the 80's will work with this powder. The bullets do not need to be seated way out in order to get more powder in the case. In testing the powder in our Bond Universal receiver against the origin "T' powder, my S.D.'s were about 30% lower with the new powder versus the "T" powder. Lou and Don Nielson donated 16 pounds of the original T-32 lot of powder for our quality control and that is what the new powder is shot against. All of our powders are allowed to deviate +3% to -5% in pressure from the quality control lot except LT-32 which we cut the deviation percentages in half in order to have the best lot to lot consistency in the industry for this powder. Another advantage of LT-32 is the fact that our Accurate 2015 can be blended with this powder if anyone wants to adjust the burn rate. 2015 is also manufactured on the machinery, has the same geometry but is about 10% slower that LT-32.

Just a note on Hodgdon's 8208. The 8208 that is being brought into the country is not being brought in for the benchrest market as most people believe. It is being brought into the country for military contracts and it just so happened that it worked in the PPC. It is being QC'd for those military contracts not for benchrest shooters. There is more money in the military side of selling powder. I work directly with the company using it for military applications. LT-32 is just the opposite. We developed this powder specifically for the 6mm PPC and it is QC'd in the 6mm PPC.



Best regards,
Keith Anderson
Western Powders Ballistic Lab

Well it was a good day for the range yesterday. Wind was kind of gusty, Temp was 37 degrees when I got there which made group shooting a little rough. Plus the fact that I had cleaned the rifles. Just took out the 12 Twist 223, 220 Swift, and my 30 year old 243 Ruger varmint.

Anyways I had some 335 loads for the 223, and decided to foul it before trying anything else. And if nothing else, 335 is great for fouling shots . First 5 shots told me what kind of day it would be. A day where I just had to pull a shot out of the group.
First 5 shots with 335 were the best. High left was the first shot.



Well the second 5 looked worse, but for 10 shots of 25.5 grains the velocity was just where I expected. 3253 fps.

Next I tried my 8208 XBR load from the other test. I could put 4 nice and tight, but the pull one out syndrome got me.



The string of 8208 went 3304 for average. The groups actually show the load has promise. Will have to revisit it.

The powder I worked with the most was LT-32. I was very impressed with this powder. Same load of 22.4 grains, Norma brass, 25 rounds GM primer, and 25 rounds BR4 primer. 5 10 shot strings went 3063, 3058, 3049, 3049, and 3049. SD's were low teens. The 5th string was shot using a mix of BR4 and GM primers, it had the highest SD of 17. This powder doesn't care what brand primer one uses.
Best groups of the day are a toss up as to a winner. Swift or LT-32. Both were 52 SMK.



The LT-32 actually put 3 into one, then I pulled 2 down a little. The Swift had 3 with 1 just a little right, then as usual pulled one up, and one down. Not quite up to bragging size but under .5 outside to outside.

Conclusion: LT-32 seems to be a very good powder, I wasn't at max, pressure was low, and there is room in the case for more powder although I don't think I need much more. Velocity was lower than predicted. Maybe blending with 2015 which is slower could bring this up a little.

8208 XBR showed real good promise on this round. I still don't like the primer issue, but will have to run the test again. This was a max book charge so velocity is what it is. Pretty much on par with the same loading of 335.

Benchmark still shows the best velocity per charge 25.5 grains was clocking in at 3416 for 10 yesterday, but groups got beat out by the LT.

Going to try the LT at a 300 yard score match next Saturday, and will see how it does at distance. I just might end up ordering an 8 lb. keg.

Good thread! Much appreciated, Swifty. My local store has no powder other than IMR 8208 and they just got in like 30-40 lbs. of it. Will pick up a few lbs. for my AR.

Swifty, thanks for posting. Your velocity variations didn't really surprise me. Regardless, those are some nice groups with the benchmark. If I can every find some around here I plan to try in in my .223.