6 XC and 115 DTACS

[rcol317]

I just have a quick question on what other's experience with 115 DTAC's. I just re-barreled a 6 XC F class rifle and in working loads the best accuracy has come with what may be a hot load but as of yet doesn't show any signs of excessive pressure. I'm shooting them 3,125 fps out of a 29" 7 twist barrel on top of 43 gr. of H 4831 SC. I shot it today to verify the data @ 600 and 1000 yards and it is shooting at that speed. Is that what other guys shoot that bullet or am I pushing it to hard? Thanks Rick

 

[rebel107]

I just have a quick question on what other's experience with 115 DTAC's. I just re-barreled a 6 XC F class rifle and in working loads the best accuracy has come with what may be a hot load but as of yet doesn't show any signs of excessive pressure. I'm shooting them 3,125 fps out of a 29" 7 twist barrel on top of 43 gr. of H 4831 SC. I shot it today to verify the data @ 600 and 1000 yards and it is shooting at that speed. Is that what other guys shoot that bullet or am I pushing it to hard? Thanks Rick

I think a little fast, i shoot mine at around 3000fps with great accuracy. If i use Berger 108's then I'm up into 3100 using the same powder. Sounds like you have jumped up to the next node.

 

[TAJ45]

Rick, I'll be in the same situation as you later this Spring when it warms up a bit - wanting to see where the pressure will top out to be a no go for brass life.

What I've planned to do unless a better method is presented to this relative noob, is to take three of my precious, processed Palma cases, and reload them at the high end, looking for a fast node, till they fail. Then I'll decide if the tariff is worth the ride.

I'm thinking that the small primer will give me the edge for 3200+ (if I don't have a "slow" 5R Krieger @ 7.5, over 30" mated to a BAT). The chambering will be a 6XC long neck of about .400, wanting to see what burying the turbulence point will do. That long neck will also allow me to reach the lands with a lighter pill w/o crowding powder capacity. Only time will tell.

Ya pays yer money and takes yer chances......just like Powerball -

 

[uashooter]

I just have a quick question on what other's experience with 115 DTAC's. I just re-barreled a 6 XC F class rifle and in working loads the best accuracy has come with what may be a hot load but as of yet doesn't show any signs of excessive pressure. I'm shooting them 3,125 fps out of a 29" 7 twist barrel on top of 43 gr. of H 4831 SC. I shot it today to verify the data @ 600 and 1000 yards and it is shooting at that speed. Is that what other guys shoot that bullet or am I pushing it to hard? Thanks Rick

Rick,

Some thoughts - please filter any input I make.

Are you running bare, or hBN coated? Are you jammed or jumped in your chamber? How deep is the DTAC seated (COAL or seating depth)?

Bare, jammed, short seated - QL thinks you are substantial over-pressure

hBN, jumped, longish - to get to 3100 fps - QL thinks you are 95% Pmax at least.

FWIW - I've a 28" 7 twist Pac-Nor. I've recently settled to a node at 39.6 gr of H4350, with a COAL of 2.839, jumping about 0.007, runs ~2890 in my barrel

I've run hBN 115 DTACS a little above 3k in some load development sets, but didn't find good groups up there.

I've gotten somewhat conservative on pressure for barrel life - and if I can find a node at 56k psi (QL estimate) I prefer that to pushing 60-63kpsi - in my mental balance, the gain in wind fighting due to increased MV isnt worth having to redevelop the load in a new barrel. There, in some estimates, might be 10-12% more life running 39.5gr at 54kips vs 43 at 60kips

Again, in my opinion(and only there....) running compressed loads can be difficult in terms of hitting and keeping seating depth when running moderate neck tension - eg to run 103% loads with 0.002 neck tension(based on bushing size only) seems to me to cause some variation in achieved and retaining seating depth. If Erik Cortina's comments on seating depth nodes only being a few thousands wide is true - then that is a fairly large concern. I know that 105% loads require different seater micrometer settings and seem to be prone(in my experience) to varying more than uncompressed loads. The powder acting as a spring is possibly another variable in the seating depth.

 

[uashooter]

Rick,

Some thoughts - please filter any input I make.

Are you running bare, or hBN coated? Are you jammed or jumped in your chamber? How deep is the DTAC seated (COAL or seating depth)?

Bare, jammed, short seated - QL thinks you are substantial over-pressure

hBN, jumped, longish - to get to 3100 fps - QL thinks you are 95% Pmax at least.

FWIW - I've a 28" 7 twist Pac-Nor. I've recently settled to a node at 39.6 gr of H4350, with a COAL of 2.839, jumping about 0.007, runs ~2890 in my barrel

I've run hBN 115 DTACS a little above 3k in some load development sets, but didn't find good groups up there.

I've gotten somewhat conservative on pressure for barrel life - and if I can find a node at 56k psi (QL estimate) I prefer that to pushing 60-63kpsi - in my mental balance, the gain in wind fighting due to increased MV isnt worth having to redevelop the load in a new barrel. There, in some estimates, might be 10-12% more life running 39.5gr at 54kips vs 43 at 60kips

Again, in my opinion(and only there....) running compressed loads can be difficult in terms of hitting and keeping seating depth when running moderate neck tension - eg to run 103% loads with 0.002 neck tension(based on bushing size only) seems to me to cause some variation in achieved and retaining seating depth. If Erik Cortina's comments on seating depth nodes only being a few thousands wide is true - then that is a fairly large concern. I know that 105% loads require different seater micrometer settings and seem to be prone(in my experience) to varying more than uncompressed loads. The powder acting as a spring is possibly another variable in the seating depth.

One other item to think about, or discard - if you dig thru the forums on the 115 DTACS you'll see some discussions about blowing them up at high speed/high spin. The Berger guys have said that high(relative) barrel friction is at least as important as the speed/spin. I've had one let go. I believe that after a barrel cleaning I may have left some Holland's Witches Brew residue in the barrel. It has some 1200 micro-inch particles, and that's what I am blaming that one on. It wasnt a particularly high MV load, and rounds before and after that one did not let go enroute to that day's 100 yd target. Because I haven't had any others let go since, I am operating on the thought that my barrel interior condition, MV, twist, etc are OK on this. If I was running 3100, I'd want to have enough rounds work before a match to know I was in the clear on the issue.

 

[rcol317]

Thanks much for all the input, I do run my DTAC's hBN coated. I was so happy with the accuracy but it does seem it would be better to back off the load and find the next lower node for accuracy. I definitely don't think it's worth the it to burn up a barrel for a little more speed, I want longer barrel and brass life in the long run. I'll bring her down and see where the speed ends up. thanks again for the advise, much appreciated. Rick

 

[Kingfisher]

I've got a 29" 1:7.5 and I get right at 3000 fps with the HBN DTAC's. That number seems to be slightly under what a lot of folks are getting. Slow barrel I guess. I can eek out 3050 with the 105 Hybrids.

 

[Cakes]

I'll toss in my 2 cents FWIW. I've been shooting a 6SLR for 5 years until recently switching to a Dasher. The SLR is quite similar to the XC. 3 different 30" barrels in my 6SLR and 43.1 of H4831sc with bare 115 DTAC's and a 1 thou touch to 1 thou off always got me ES under 10 and 2985'. This with Tula or BR-2. When it would get warm this was very close to max load for all 3 barrels. You must have a VERY slippery barrel to get 3100+ with the same load. H1000+DTAC's also worked well and H4350 with 107SMK's @ 3100+ is another good combo. Have fun, Eric in DL

 

[dunraven]

I just have a quick question on what other's experience with 115 DTAC's. I just re-barreled a 6 XC F class rifle and in working loads the best accuracy has come with what may be a hot load but as of yet doesn't show any signs of excessive pressure. I'm shooting them 3,125 fps out of a 29" 7 twist barrel on top of 43 gr. of H 4831 SC. I shot it today to verify the data @ 600 and 1000 yards and it is shooting at that speed. Is that what other guys shoot that bullet or am I pushing it to hard? Thanks Rick

bought a barreled action in 6XC n put an AI stock on it, using it for some long range tactical out to 900. found the 115 DTACs shot better than any 105s in 1:8. using 39.4 gr H4831sc. RL 17 about equal in precision. this is my first rifle in this caliber but i would definitely build another.