115 DTAC - jump or jam?

[Goin'Hot]

I'm loading for a 243ai. I've tried Hybrid 100 with the DTAC's jumping 0.005". My groups can be measured in inches rather than fractions of an inch. I don't know if I should try another powder or change my seating depth. What do you guys find is a good jump for these bullets?

8 twist 3 groove barrel that's been Nitrided.

 

[BOLTRIPPER]

Re: 115 DTAC - jump or jam?

i would jump 'em, you will eventually with a AI

 

[Dustin Morris]

Re: 115 DTAC - jump or jam?

Try H1000 Instead of the Hybrid. I shoot 47.2 grains behind a 115 in lapua brass in a standard 243, so it should be plenty safe in an AI

 

[Immorteq]

Re: 115 DTAC - jump or jam?

Some folks claim the 1-8tw is too slow for 115's but at AI velocities I'd keep workin with em a bit and check out this thread...

http://www.accurateshooter.com/forum/index.php/topic,982860.0.html

 

[Goin'Hot]

Re: 115 DTAC - jump or jam?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: SevenBat</div><div class="ubbcode-body">Try H1000 Instead of the Hybrid. I shoot 47.2 grains behind a 115 in lapua brass in a standard 243, so it should be plenty safe in an AI </div></div>

Barrel length is 28". I've got plenty of H1000 around. I shoot it in my EDGE. I was afraid it was too slow for the ai. I'll give it a try.

What kinda jump are you using? I'm running Lapua brass as well with Win primers.

 

[Goin'Hot]

Re: 115 DTAC - jump or jam?

I just loaded some H1000 pressure loads. 46-50 grains with a .010" jump. COAL measures 2.815". Next dry day, I'll head to the range.

I was starting to crunch powder at 49 grains.

 

[DocB]

Re: 115 DTAC - jump or jam?

GH,

I use between 0.025" and 0.050", I find them to be rather tolerant of the amount as long as you use the minimum I've listed. This is in a regular .243 with a 1/8 twist.

HTH,
DocB

 

[Goin'Hot]

Re: 115 DTAC - jump or jam?

Well, maybe I'll go push them a little further in. I'd be interested in knowing what oal sevenbat is running.

 

[craigp40]

Re: 115 DTAC - jump or jam?

I have a similar set up with my AI (8 twist Rock barrel - 26"). Never tried H1000, but did try RL-25. Velocity was great, but never could get the accuracy I was looking for. I'm now running H4350 and seating them 0.005 off. With mine, I've noticed that accuracy goes to hell when I try to push the DTACs hard. My current load is somewhat conservative sitting at 3020 fps, but it drills them nicely.

 

[Shooter21]

Re: 115 DTAC - jump or jam?

I'm only .001" off the lands with 115s over 42.2 of H4350 in a regular 243 with an 8 twist 24" barrel.... it shoots like a bench gun, but I don't...

Edit: it is a 6 groove and land Shilen select match.

 

[MTETM]

Re: 115 DTAC - jump or jam?

I jump them .010 in 2 rifles. Shoot fantastically. I found when testing at 500 that I had significantly more vertical when they where jammed...

1 barrel is a 1:7.5
1 barrel is a 1:7.75

 

[knockemdown]

Re: 115 DTAC - jump or jam?

Also thinkin' you may need more twist in your tube?
Can you shoot them on paper to see if they are keyholing?
I've read that some guys can get away with a 1:8" with the DTACS, but being I'm in the NE at <1000 ASL in often humid air, I opted for more twist...
Mine is a straight .243 from a 26", 1:7.5" Rock 5R and I'm runnin' RL-25. It hammers. Tried H4350 on work up, but wasn't getting all the speed, 2920-ish before pressure. '25 gets me another 100+fps over that, 2.860" in a GAP 'match' chamber. Never measured jump, just loaded to mag length & shot it...

Maybe try the 105Amaxs in yours?

 

[chooter]

Re: 115 DTAC - jump or jam?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Immorteq</div><div class="ubbcode-body">Some folks claim the 1-8tw is too slow for 115's but at AI velocities I'd keep workin with em a bit and check out this thread...

http://www.accurateshooter.com/forum/index.php/topic,982860.0.html </div></div>

According to the JBM ballistics stability program the 115 DTAC will stabilize in an eight twist barrel at least as slow as 2600fps. I intend to use this bullet in a 15" barreled pistol for long range shooting.

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.1.cgi

 

[RTH1800]

Re: 115 DTAC - jump or jam?

I think the T2K is an 8 twist Schneider.

 

[jasonk]

Re: 115 DTAC - jump or jam?

.010 - .015 is a good place to start with them.

 

[Jeffvn]

Re: 115 DTAC - jump or jam?

+1 start at .010 - 0.015 and then see where she takes you. Mine like .010 jump. my Berger 108s like the same spot.

JeffVN