Home Forums Hunting & Shooting AR and Tactical Rifles 24HC Black Rifle Challenge Thread

BTW we shoudl get Denton in here, isn't there some numerical theory that uses 7 as statistical?

Regardless, to me, to mean aything your gun has to be repeatable, and I'm not sure of what mine do until they've been shot quite a bit for at least a year.

I have deer rifles that may never get shot enough to become statistical....

I printed out the targets, was hoping to shoot them today. Given the wind that's not likely. This eve or tomorrow hopefully.

That depends on the difference in your standard deviations. It takes a sample size of 30 to move from the T table to the Z table, but that does not mean you cannot achieve statistically significant results with a smaller sample.

Depends on how accurate you want to be.........

With enough 10 shot groups & a consistent enough SD to validate a normal distribution of the 10 shot groups, yes, but the single 30 piece sample solves any if's and's or but's.

YMMV.

MM

ten is a convenient sample size. Take the total variation in 10 pieces of data, double the range of those 10 pieces, and you have very close to ± 3 sigma

You guys make this way more complicated than it is. As long as critters die when I pull the trigger, I'm happy.

And they have!

And the rules state 2 10 shot groups, why doesn't matter.

I tried again today and followed the challenge with some load development. Either my barrel doesn't like 75/77gr pills, doesn't like Reloader 15, or I am just a 1.5-2 MOA shooter. I know I had good trigger control and a natural POA, I just can't get this barrel to group good for me with the heavy bullets. Maybe Frank White will take it back and check it out??? Overall, rough day today with the black guns.

On a birghter note, here is a group from my Sako TRG at 400 yards. Just a hair under 1/2 MOA with a 178 BTHP moving 2750fps.

My last barrel would absolutely not shoot 77gn Nosler or 77gn SMK but would shoot great with 75gn Hornady OTM bullets. Also shot great with 69gn bullets, either Sierra or Nosler (which by they way it's time to update the leader board). It didn't matter what powder, charge, primer, etc. it would not shoot the 77gn bullets better than about 1.5 MOA and often shot them closer to 2 MOA.

Well, I will try Varget and TAC next before I look at replacing it. If it won't shoot the 75/77's its not worth having as thats 90% of what I load for .223.

Current Rankings:

Optics:
1) scenarshooter: .475 MOA (page 6)
2) KeneticPerformance: .819 MOA (page 8)
3) jimmyp: 1.085 MOA (page 5)
4) TWR: 1.110 MOA (page7)
5) Certifiable: 1.155 MOA (page 5)
6) wareagle700: 1.246 MOA (page 1)
7) BGunn: 1.265 MOA (page 2)
8) 348srfun: 1.449 MOA (page 7)
9) tex_n_cal: 1.461 (page 5)
10) jimmyp: 1.537 MOA (page 5)
11) fredIII: 1.736 MOA (page 5)
12) Formidilosus: 1.787 MOA (page 4)
13) Mathsr: 1.928 MOA (page 4)
14) wareagle700: 1.968 (page 5)
15) TWR: 2.308 MOA (page 1)

Iron Sights:
1) rost495: 199-8x / 1.351 MOA (page6)
2) wareagle700: 167-0x / 3.320 MOA (page 1)

I was hoping to shoot it today, too, but the wind was cranking. Couldn't fish, either.

There is a reason they make full 7 twist barrels.... anything like a 75/77 has always shot much better for me in the 7s. Before going to 90s, we shot 7.7s for a while, and then moved to full 7 twist and life was much better, especially at longer distances. The 6.5 twists we ended up with shot the 77s ok too.

4 inch square plate, seems fairly tough steel from the looks of it. Nice group. Answers your own question if you can shoot or not....

Once you know you shoot good, when a gun doesn't group, its the gun. You know when you screw up, at least I do.

Like the coach said, call that shot( meaning tell me where you think you hit, from what you saw when the gun went off, so he can understand why the bullet hit where it did) .... Ummm ( my shot call instead of saying mid ring 9 at 10 oclock) ... Come BAAACCCKKKKKKK

I'm glad the revered Rick Jamison thinks a 10 shot gropu of 1.5 inches is a good group. I don't think it is at all.

Of course I also think that a lot of supposed .5 moa guns are actually more like MOA when it comes down to reality.

my thinking as well, this barrel shoots 55 grain VMax bullets, but it sucked with 77 and 75 grain bullets. I shot the match with 55 grain bullets.

That plate pictured above is actually a 8" plate. The group looks bigger because of the paint missing. It might be tough to tell from the pics but there's 2 hits to the left and 3 about 2" to the right.

The barrel I have is a 18", 7 twist, Douglas from Compass Lake Engineering. I know it's not a top shelf cut rifled barrel but I figured it would at least shoot MOA with match handloads. I'll try some different powders before I start calling though. I dont claim to be an expert marksman by any means, especially with gas guns, but this barrel just doesn't seem to like what I'm doing.

Then your results are similar to mine with Douglas. Even though others have had really good luck with them, evidently i've managed to buy 3 lemons from them, and I won't ever again.

I remember you saying that. My experience with Douglas has been good, I hope it continues. I pulled the barrel this morning and reinstalled with a lower torque value. Originally it took 85 ft/lbs to get the nut to align. I lapped the face of the receiver a little more to get the nut to align at 55 ft/lbs today so maybe that did something. I also bedded the extension to the upper with a little loctite. I know its put together right, I know my loads are consistent, and I have no doubts about my optic and mounts holding up. If I can't get it to shoot, I will look at replacing it somehow.

I like mine around 40 but had a Colt HBAR once that would shoot at well over 100 ft lbs. I broke the upper getting it off. Put a new upper on it with the free float tube and it shot the same. Figured floating it and loosening the nut would've helped but it didn't.

I've had good luck with Douglas barrels but mine have all been #1 contoured bolt guns. Then again, I don't shoot like Jeff does and probably couldn't tell the difference between what he calls good and bad.

I feel you. All I shoot are 75/77gn bullets for DMM out of that gun. I use the 69gn bullets some for shooting alts on my home range as it only goes to 300yds. If a barrel won't shoot the 75/77gn bullets I don't want it. I nearly scrapped that last barrel when it wouldn't shoot the 77gn SMK or NCC but once I figured out it would shoot the 75gn Hornady OTM I just ran with it.

Another load to try:

Just did the ladder testing with this powder a week or two ago. Previously I had not tried it. I think it is a little on the fast side but at that velocity I am getting a properly gassed combination with pretty good precision and deviation.

I run mine up to around 35-45 generally. Then I cut off or whatever, to keep it there and get the gas tube through... generally a hole or a star "tit" needs grinding or nipping.

I don't THINK you can affect accuracy at the chamber area, but I do think on skinny tubes you could torque a flash hider or such tight enough to affect things.

After all I think you'd break the upper being its AL, before you 'squeeze" steel.

I have a guy I really trust, that is learning to rebarrel. When he is happy, I'll have one more go at a douglas possibly. But the last I had done was by Mickey, and every other gun he did was easy sub moa with Rock tubes, the one douglas is barely MOA if that just depending. Granted I've only tried 4 different powders and 3 different bullets, with weight sorted fire formed brass, but it just drove me nuts enough that it sits in the safe and I don't shoot it.