Rifle throwing shots with 115 Dtac

[Wisconsinner]

Good afternoon! I went out yesterday to confirm a load of H4350 and 115 naked dtacs yesterday afternoon. I loaded 10 rounds at my suspected velocity node running about 2980. First group stacked 2 on top of each other, then a bad flier 2" to the left of my point of aim, 4th grouped with the first 2, and the last shot flier. I was also fire forming some brass with a light charge of H4350 and 105 vld hunting bullets. Shot a few 5 shot groups of that lights out. Went back to the last load with the dtac bullets and had 4 group nicely, and another flier 2" left of point of aim.. WTH! I am maybe 200 bullets into this lot, and the first lot shot well.. Anyone see this before?

 

[davidjoe]

If the rifle groups 105’s but has flyers with 115’s, and I were to hazard a guess why, it would be that the twist rate of the barrel is right on the edge of what will and will not work for that long bullet. That’s a great bullet, though.

 

[Wisconsinner]

Thank you for the reply. The barrel is a 1:7.5. It's the first time seeing this. I have shot bullets from lot that were great. I'm planning on a few groups from an unopened box I have along with the ones in question.

 

[dstoenner]

i would scrub the throat with jb paste. Also check the muzzle just to be sure.

i shoot dtacs with h4350 with great results. 1:7 barrel and my velicity is 2950

 

[Wisconsinner]

i would scrub the throat with jb paste. Also check the muzzle just to be sure.

i shoot dtacs with h4350 with great results. 1:7 barrel and my velicity is 2950

I will give that a try. Jb paste on a brush work ok?

 

[Ranger188]

I have heard this problem a few times about the 115 DTAC's
You are not the first.
Sometimes you'll get a good batch and next time one that
will throw a flier or two.
I stopped using them for just that reason.
I was also using a 7.5 tw so shouldn't have been the problem.

 

[6ShotsOr5?]

I have heard this problem a few times about the 115 DTAC's
You are not the first.
Sometimes you'll get a good batch and next time one that
will throw a flier or two.
I stopped using them for just that reason.
I was also using a 7.5 tw so shouldn't have been the problem.

@Ranger188, Did you do any measuring to see if you could see any differences on the lot that was throwing flyers?

 

[dstoenner]

I will give that a try. Jb paste on a brush work ok?

Yes i have seen it work. I had a 6br with 3000 rounds that started loosing accuracy after about 20 rounds from cold clean. I used jb bore paste and really scrubbed it down. Next range trip the barrel went a 60 rounds and turned in one of the best targets i had shot. I knew the barrel was almost gone but jb gave it on last shot, pun intended. I first soak the bore with kroil and then i use a patch over a Montana extreme nylon bore brush.

I have only shot 2 lots of dtacs. Both were great. My new box of 500 i sorted on oal of the bullet. I had over 400 that were within .005 of each other, 81 in the next .005 and the rest were under and over but the whole lot was not over.014 from each other.

i just changed barrels and tomorrow i am starting a load work up with my 3rd lot of dtacs. I’ll let you know how they turn out

 

[Ranger188]

No I never did any type of measurements.
I was load testing @100yds. and would put 2 into the same hole and throw one out.
Did quite a few times.
They would group like this when they were on.

 

[Longtrain]

JB is great stuff IMO, about every 300 rounds my barrels get a good scrubbing, although I really don’t see copper until the barrel is getting up in age (>2000 Dasher rounds). I do get carbon and JB is the only thing that get it out, I’ve tried most things on the market. I use patches over a worn brush, slather JB and clean away. It takes as long to swab out all the JB goo as cleaning. But a bore scope will tell you when it’s really clean, and yes I still have rifling in the barrel up to it’s dying day.

 

[TAJ45]

I'm sure this doesn't apply in the case of the OP, But..... I bought a used CZ 17 HMR shortly after debut. It would put 2 touching at 100yds then toss one put aother back in the group etc. No pattern, no rhyme or reason....until I found the reason.....minute burr(s) on the crown. It took a Q tip and a magnifying glass.