Best accuracy to be expected? Semi-auto DMR

[sirriccus]

5-shot groups are consistently 1/2 MOA. I believe there's still more in it. Played around with the seating depth a little, but I can make more precise adjustments to hopefully get her in the 1/3 MOA category.

6.5 Grendel DMR (AR platform I built)

I've also heard that the ELD-M's are doing better than the SMK HPBT's so that will be something I try as well.

I have shot 1/4-1/3 MOA groups, but not consistently enough for me to claim it's repeatable and not just a fluke. Nor am I the best shooter. I'm working on it.

28.0 gr. 8208 XBR
123 gr. SMK HPBT
Hornady brass (once fired)
1.6490" OGIV
CCI 450 (small rifle magnum primer)

(10 rounds)
2,563.1 average velocity
4.8 standard deviation
12 extreme spread

.4703 MOA
.4980 MOA

(5 rounds)
2,569.2 average velocity
4.1 standard deviation
10 extreme spread

1.6550" OGIV
.5530 MOA

IMG_0674.JPG
IMG_0675.JPG

[LRRPF52]

Very nice. What barrel did you use?

[biodsl]

(10 rounds)
2,563.1 average velocity
4.8 standard deviation
12 extreme spread

.4703 MOA
.4980 MOA

(5 rounds)
2,569.2 average velocity
4.1 standard deviation
10 extreme spread

1.6550" OGIV
.5530 MOA

I want to know your reloading techniques. Outstanding!

[1911man]

5-shot groups are consistently 1/2 MOA. I believe there's still more in it. Played around with the seating depth a little, but I can make more precise adjustments to hopefully get her in the 1/3 MOA category.

6.5 Grendel DMR (AR platform I built)

I've also heard that the ELD-M's are doing better than the SMK HPBT's so that will be something I try as well.

I have shot 1/4-1/3 MOA groups, but not consistently enough for me to claim it's repeatable and not just a fluke. Nor am I the best shooter. I'm working on it.

28.0 gr. 8208 XBR
123 gr. SMK HPBT
Hornady brass (once fired)
1.6490" OGIV
CCI 450 (small rifle magnum primer)

(10 rounds)
2,563.1 average velocity
4.8 standard deviation
12 extreme spread

.4703 MOA
.4980 MOA

(5 rounds)
2,569.2 average velocity
4.1 standard deviation
10 extreme spread

1.6550" OGIV
.5530 MOA

[ATTACH=CONFIG]8580[/ATTACH]
[ATTACH=CONFIG]8581[/ATTACH]

Very nice, its hard to get much better than true 1/2 MOA performance in any caliber and especially a gas gun. I really appreciate the fact that you have done a fair amount of testing and even admit that though you have shot 1/4 MOA groups that they are not as common. Too many times people will come on sites like this one and say there gun is 1/2 MOA accurate because they can get 3 shots to perform that way and they dismiss anything outside of that as a "flyer". I also hear people blame themselves and say they pulled the shot that made the group an MOA group instead of a 3/4 MOA group. That is why you have to do thorough testing to determine just how accurate your gun is. Alot of guns can put up that occasional 1/2 MOA group but if you tested 10 or more 5 shot groups you would see a much higher average.

What barrel are you running? That is some pretty good velocity for that charge of XBR, I am guessing you have a 24" barrel. Your SD and ES are excellent on that load as well. Good work.

[sirriccus]

Very nice. What barrel did you use?

Thanks! Shilen 20" HBAR 1/9 TWIST 5/8x24 threaded

I want to know your reloading techniques. Outstanding!

Thank you! I just recently started going that extra little bit. Purchased a much more accurate scale. Had 4 so far and haven't been very pleased with any of them. But I'm beginning to trust in the Gem Pro 250. Also started sorting cases and bullets by weight which definitely made a small difference. Aside from that, I've got comparators for headspace measurements and OGIV measurements as well as seating depth gauges that allow me to see where I'm seating the bullet in conjunction to the lands which is fairly important (Jumping the bullet .0040"). Micrometer stems for seating dies are a must.

I'm excited to share that I also have an annealing machine and K&M neck turner in route as well.

I have an issue with getting into a hobby a little too much and I'm falling victim to it now. I've only been reloading for a couple of months.

Very nice, its hard to get much better than true 1/2 MOA performance in any caliber and especially a gas gun. I really appreciate the fact that you have done a fair amount of testing and even admit that though you have shot 1/4 MOA groups that they are not as common. Too many times people will come on sites like this one and say there gun is 1/2 MOA accurate because they can get 3 shots to perform that way and they dismiss anything outside of that as a "flyer". I also hear people blame themselves and say they pulled the shot that made the group an MOA group instead of a 3/4 MOA group. That is why you have to do thorough testing to determine just how accurate your gun is. Alot of guns can put up that occasional 1/2 MOA group but if you tested 10 or more 5 shot groups you would see a much higher average.

What barrel are you running? That is some pretty good velocity for that charge of XBR, I am guessing you have a 24" barrel. Your SD and ES are excellent on that load as well. Good work.

Thank you! I appreciate the reply.

Shilen 20" HBAR 1/9 TWIST 5/8x24 threaded

The loading seems to be getting better and better with more experience so I have high hopes that it will at least remain consistent at these numbers. Hopefully even get slightly better.

I'll post the pictures for you guys shortly. I would be confident in saying it's a 1/2 minute rifle with me behind it right now. I'm certainly aiming for 1/3 minute consistency eventually. I also just got a new scope (Vortex Razor HD Gen II 4.5-27x56) with a 20 MOA Bobro cantilever mount so my 100 yard zero is now at the 3 MIL hashtag above the crosshair. I'm not making excuses, but it was fairly challenging for me to remain consistent on the target when I didn't have my horizontal line matching the target horizontal line. I managed in the end, but while shooting, I wasn't nearly as confident as I usually am.

[sirriccus]

IMG_0679.JPG
IMG_0680.JPG
IMG_0681.JPG

[Klem]

That's unbelievable - Well done!

[dammitman]

you have a gun and ability to use it that I would really like to copy,,,,,i have that same exact barrel and its pretty dam accurate but I feel that the difference is in the trigger puller!!!!

[sirriccus]

That's unbelievable - Well done!

Thank you!

you have a gun and ability to use it that I would really like to copy,,,,,i have that same exact barrel and its pretty dam accurate but I feel that the difference is in the trigger puller!!!!

I appreciate that. I would just like to reiterate that it's definitely the ability to develop a specific load for this particular weapon system. Factory ammo was all around 1 MOA (including Hornady AMAX and SST). I began developing my pet load and started seeing the capability of the rifle. If I would have known that this is why people lean towards reloading versus saving money, I would have done it years ago.

[1911man]

The velocity your getting out that combo and your 20" barrel makes me want to break out the XBR for my barrel. I have 2lbs of it but actually found it to be slower than AR comp in my last barrel. I am going to give it a try next trip to the range.

[AZ. Old Guy]

Measuring center to center would be smaller wouldn't it?

[Fredman]

Measuring center to center would be smaller wouldn't it?

Yes. Subtract .264" from each group will give center to center.

My thoughts are if 90% of your groups are like those, forget load development, go out and have fun! Golf balls at 300?

[1911man]

Yes. Subtract .264" from each group will give center to center.

My thoughts are if 90% of your groups are like those, forget load development, go out and have fun! Golf balls at 300?

Yeah and his SD on that load is probably as good as it gets showing that this load is a winner.

[Rickc]

This is a shilen hbar. Worked a long time to get it this good. Your results are exceptional

[IMG][/IMG]

[Rdavis]

[IMG][/IMG]
[IMG][/IMG]
[IMG][/IMG]
Here are a few pics of groups I am getting with mine.
Handloads with a JP barrel.