DTACs jammed?

[bm11]

Just curious if anyone else has noticed DTACs liked to be run jammed. After determining charge weight, I ran a test from .030 off to .015 in, defining the "0" as the point where the 5 land marks can no longer be seen on the bullet, but .001 longer and they can.

The loads jumping were all around 3/4 moa, but shrunk to .3 moa at 0 and held there until .015 jammed, where it opened up to over half moa.

ES was in the low teens with single digit SD for the jammed bullets, and not as consistent jumped, so in this barrel, jammed seems to be the ticket for now.

Continuing further, I got a new batch of RL-25 in, and it turned out to be faster. I couldn't get the load to shoot better than 3/4 moa, old powder or new, so I finally remeasured and found that my throat had grown .0075 and what I thought was kissing the lands was actually jumping.

I am curious if anyone else has found similar results with DTACs?

-Bob

 

[Ouch!!]

Re: DTACs jammed?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body">Just curious if anyone else has noticed DTACs liked to be run jammed. After determining charge weight, I ran a test from .030 off to .010 in, defining the "0" as the point where the 5 land marks can no longer be seen on the bullet, but .001 longer and they can.

The loads jumping were all around 3/4 moa, but shrunk to .3 moa at 0 and held there until .015 jammed, where it opened up to over half moa.

ES was in the low teens with single digit SD for the jammed bullets, and not as consistent jumped, so in this barrel, jammed seems to be the ticket for now.

Continuing further, I got a new batch of RL-25 in, and it turned out to be faster. I couldn't get the load to shoot better than 3/4 moa, old powder or new, so I finally remeasured and found that my throat had grown .0075 and what I thought was kissing the lands was actually jumping.

I am curious if anyone else has found similar results with DTACs?

-Bob </div></div>

Interesting, I have mine jumped .015 and the shoot about 3/4moa until 200 then the shrink to less than 1/2 moa after that until around 800 which ia the farthest I have shot so far for groups.

 

[bm11]

Re: DTACs jammed?

That is interesting. The jammed loads performed well at 650 for the limited groups I shot, and of course they performed well on steel.

 

[Wes3377]

Re: DTACs jammed?

Hello all! First post and just getting used to the forum layout, but I felt I could contribute here as I am currently working on a load to go from 105 A-max to the Dtacs in my .243 AI.

I have noticed that the Dtacs do like to be touching or slightly in to the lands. Re19 and Re22 have been just under half MOA at 200, which is where I do my fine tuning, with the bullet just touching. Even .005 off the lands opens up groups to 3/4 MOA and gets steadily worse from there. The A-Maxs on the other hand, did prefer a slight jump.

I am by no means a reloading expert, but those have been my Dtac observations in the last 65 rounds.

 

[725franky]

Re: DTACs jammed?

This is some good information as I am preparing to develop a .243Win load using 115DTACs. I'll be watching to see what most people seem to find works for them.

 

[Ouch!!]

Re: DTACs jammed?

What powder you using bm. I'm shooting h4350. What kind of rifle and twist.

 

[bm11]

Re: DTACs jammed?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Ouch!!!!</div><div class="ubbcode-body">What powder you using bm. I'm shooting h4350. What kind of rifle and twist. </div></div>RL-25. Barrel is a GAP Bartlien 28", 7.7 twist Tubb contour on a AIAX.

 

[Nocalphoenix]

Re: DTACs jammed?

Im running the dtac .020" off with H4350 and the results have been awesome. I needed them mag length and with 1200 rounds through the rifle I have not needed to make any adjustments for throat erosion at all.

This is after 1000 rounds, action, poi was moving a bit as I was playing with the scope.

 

[MTETM]

Re: DTACs jammed?

Bob,
I had been jumping the DTAC's .015 and they had shot very well until recently.
I ran some groups today following my wife commenting on a lack of consistency in her rifle.
After more than 1000 rounds on one rifle and 1800 on the other shooting DTAC's I am in agreement with you. The groups tighten up when they are jammed.

The throat on 1 rifle has extended .03 over the past 800 rounds. I had not checked nor adjusted the seating depth.
The 2nd rifle has grown .03 over the past 1000 rounds and has not moved in the past 300 rounds.

Today I started at .05 off and worked out to .025 off, the results were progressively worse. They started with horizontal stringing, great vertical, but MOA plus wind. At .025 they were round MOA groups.

When I was tired of the jumping, I jammed them .010 and both rifles were back to shooting nice little holes.

I then put them on cleanly painted steel at 500 and had good round half moa groups.
Long and short...I will jam them from now on and pay more attention to the throat length.

 

[tcasexx]

Re: DTACs jammed?

Have you tried jumping them .060 or .090 mine worked in my 243 at .120 of the lands

 

[TEAMSENDIT]

Re: DTACs jammed?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: tac driver</div><div class="ubbcode-body">Have you tried jumping them .060 or .090 mine worked in my 243 at .120 of the lands</div></div>

thats funny couple of my buddies noticed the same exact thing and they both shoot theres 80 thou off the lands.