115 dtac vs 105 hybrid

[MOShooter]

My 6slr shoots the 105 class bullets well. However, only at 2900fps. I've tried different powders and bullets. They all hit the same node at 2890-2910. I've excepted that is the sweet spot for this barrel. I've been wondering is I would have the same node with 115 dtacs and could gain any down range performance. I believe the BC is .547 for the hybrid and .585 for pointed dtacs. I think I can push them up to 2900 since I'm running a fairly light load with the 105s. Also will my 1-7.5 stabilize the dtacs?

Scott

 

[DocBII]

MOshooter,

Your rifle has enough twist, but the node for the DTACs mat be different. I'm using Norma MRP in my .243s to move the Berger 105 Hybrids @ 3000, which is the speed limit at my range. The DTACs like either 2900 or 3150 out of my rifles.

I have found the DTACs need to be sorted by ogive length for best results. The Bergers don't have as much variation, but it still helps to sort them. Sorting gets rid of the really odd bullets in either case.

HTH,
DocB

 

[tonysnoo]

Hey Scott,
I used to shoot DTACs out of a 7.5 twist 28" barrel at just under 2900. The 105 hybrids were running 3030 with 4831sc, so I stayed with the lighter bullets.

I am assuming you are running a shorter barrel. You might try a slower powder???? I now run 7828 and it appears to work well in my new 26" barrel (3050fps)

 

[MOShooter]

Hey Scott,
I used to shoot DTACs out of a 7.5 twist 28" barrel at just under 2900. The 105 hybrids were running 3030 with 4831sc, so I stayed with the lighter bullets.

I am assuming you are running a shorter barrel. You might try a slower powder???? I now run 7828 and it appears to work well in my new 26" barrel (3050fps)

Yes. I'm running a 24" tube. I've tried H4831 and H1000. Both had pretty much the same results. I was able to get higher velocity from RL26 but the accuracy wasn't as good. I'm currently running the standard load for this round of 43.5gr of H4350. I've ran up to 44.6 before I got flattened primers but again the accuracy want there.

Scott

 

[Tahoe Shark]

Hey Scott,
I used to shoot DTACs out of a 7.5 twist 28" barrel at just under 2900. The 105 hybrids were running 3030 with 4831sc, so I stayed with the lighter bullets.

I am assuming you are running a shorter barrel. You might try a slower powder???? I now run 7828 and it appears to work well in my new 26" barrel (3050fps)

Oh man, not another rifle! You were tough enough with your old rifle.

 

[Hengehold]

My 6slr shoots the 105 class bullets well. However, only at 2900fps. I've tried different powders and bullets. They all hit the same node at 2890-2910. I've excepted that is the sweet spot for this barrel. I've been wondering is I would have the same node with 115 dtacs and could gain any down range performance. I believe the BC is .547 for the hybrid and .585 for pointed dtacs. I think I can push them up to 2900 since I'm running a fairly light load with the 105s. Also will my 1-7.5 stabilize the dtacs?

Scott

The BC for DTACs in Brian Litz's first book indicates that the 115 DTAC has a lower BC than the 105 hybrid. Litz's measured BC value for the DTAC was noticeably lower than Tubb's estimated BC for that bullet.
Therefor, since you can push a lighter bullet faster, the hybrid is a better choice as far as wind drift is concerned.

-Trevor

 

[swd]

The DTAC's I've shot were spot on in drop to .587 BC Tubbs claims.

 

[tonysnoo]

Yes. I'm running a 24" tube. I've tried H4831 and H1000. Both had pretty much the same results. I was able to get higher velocity from RL26 but the accuracy wasn't as good. I'm currently running the standard load for this round of 43.5gr of H4350. I've ran up to 44.6 before I got flattened primers but again the accuracy want there.

Scott

Hey Scott,
I always thought the standard to be 43.5 of H4831sc. You are the first, Ive heard running 4350. I was worried about 7828 in the shorter barrel. I did lose about 75fps compared to my 28" but gained accuracy....not necessarily apples to apples...but this new barrel likes the 7828. I will test with 4831 too. Keep us informed on your progress...good luck

Hey Tahoe,
gotta keep up with you two....its hard work!

 

[clowdis]

The Hodgdon website is showing higher velocities with the new IMR Enron powders than with the older 4350 and 4831 powders.

 

[Dgd6mm]

The BC for DTACs in Brian Litz's first book indicates that the 115 DTAC has a lower BC than the 105 hybrid. Litz's measured BC value for the DTAC was noticeably lower than Tubb's estimated BC for that bullet.
Therefor, since you can push a lighter bullet faster, the hybrid is a better choice as far as wind drift is concerned.

-Trevor

This is correct, that is in his first book. Since then and with them being pointed they are now .585

 

[zipollini]

What does Litz list the G1 and G7 BCs for both the Hybrid 105s and the new pointed DTACs ?

 

[ballison]

What does Litz list the G1 and G7 BCs for both the Hybrid 105s and the new pointed DTACs ?

This is from AB Profile loader for my Kestrel, and was updated fairly recently. Take it for what its worth.

115 DTAC G1=.276 G7=.539
105 Hybrid G1=.275 G7=.536

 

[zipollini]

Thanks FTRinPA - Just what I was looking for. Try as I might I just can't seem to figure out a reason to shoot the 105 Bergers when I already shoot the Hbn coated DTACs.

 

[SHootSTraight22]

G1 is .590 pointed I thought... .575 not pointed (Litz # is .540) These numbers are from JBM for the DTACS... The hybrids have a higher BC than that... .276 G7 is Litz number for non pointed DTAC...

 

[MOShooter]

Hey Scott,
I always thought the standard to be 43.5 of H4831sc. You are the first, Ive heard running 4350. I was worried about 7828 in the shorter barrel. I did lose about 75fps compared to my 28" but gained accuracy....not necessarily apples to apples...but this new barrel likes the 7828. I will test with 4831 too. Keep us informed on your progress...good luck

Hey Tahoe,
gotta keep up with you two....its hard work!

That was a typo. I'm running 43.5 H4831. I've decided in the name of barrel life I'm just going to stay with my hybrid load for this season.

Scott