Anybody running a 6GT with 115 dtacs? Might switch over from 6 creed at end of prs season. How is the 6 gt performing for those of you running it?
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6GT with 115 dtacs
- Thread starter Jarrodb1975
- Start date
I shoot them in my GT. Then shoot really well but obviously slower. I hit press with Hornady brass right around 2900 fps. So I load in a node at 2850ish. I would imagine that thicker alpha brass with be even slower.
That’s kinda what I was expecting I get 3060 with the dtacs with my 6 creed but dealing with a bit more recoil. What powder are u running?
I run 109 bergers, 33.4 varget, alpha brass on 6th firings, 28 inch barrel I get about 2940. My last barrel had 1800 rounds before it started to open up to 1 inch groups. Just got a bartlein for a try and it hammers but I'm hoping this barrel lasts longer. Time will tell.
I tried everything under the sun with varget being so hard to find. 6.5 StaBall, h4895, h4350, and finally some varget.
6.5 StaBall was decently fast but not good ES, SD. H4895 was way slow and h4350 was ok (2850 before pressure).
Varget is definitely the way to go. Much larger nodes and faster than everything else.
6.5 StaBall was decently fast but not good ES, SD. H4895 was way slow and h4350 was ok (2850 before pressure).
Varget is definitely the way to go. Much larger nodes and faster than everything else.
I have the new OCD brass and ran them up to 3000 with a 25.5” hart barrel. I haven’t even got an ejector swipe. That being said, there’s a node right around 2920 and that’s prob where I’ll be running them. Doing group testing tomorrow with diff oal’s we shall see how she goes.
What powder are you using? I assume that's the standard .120" freebore that all the reamers from GAP are using?
I'm toying with ordering a .150 to .180 freebore reamer from Manson just to shoot 115 DTACs. Might get a little less pressure and get that bullet to sit at the neck juncture a little better.
Yes that’s the standard GAP reamer. The 110’s and the 115’s both shot very good. Both are running just around 2940. And running H4350
Thats great info, thanks.
And it doesn't sound like anyone is having to neck turn Hornady brass with the .273 neck dimension on those standard reamers?
I haven’t heard of anyone neck turning for GT (that doesn’t mean no one does). But there’s no reason to IMO. Both the alpha and hornady run just fine without turning.
Thank you for the replies. I like to buy the reamer to chamber my rifles, but I've bought a few reamers that weren't really the correct dimensions. So I've become cautious about making sure everything is correct as I need it before ordering.
I'm not a fan of PT&G for multiple reasons, so I dont want the reamer GAP sells. The JGS they are now offering is excellent quality, but I can get a Manson reamer, whom I've had excellent results with for $100 less with the Go Gauge included. So just dotting i's and crossing t's before ordering.
In my 6 Creedmoor, the 115gr DTACS liked to be jumped around .020 to .030".
My GT is still under construction, but I suspect that's where they will end up.
I bought a throater from Manson. Im pretty sure if I want to get that boat tail seated above the neck shoulder junction I'm going to have to bump that freebore to about .170". I dont like having the bullet seated into the case.
Awesome! Thanks for the response! I really appreciate a rough starting point. I have a bit of RL-16 left and about 4 lbs of 17. I wanted to start running load dev for if/when people start selling primers at normal price and not on GB again!
I built my 6GT with a .170" FB expecting to run DTACs. (Hornady virgin brass, CCI primers, H4350 powder). It was a new cartridge and new bullet for me. Now, I don't think 0.170" is enough....
I'm in the lands at 2.590" COAL. I'm at the neck shoulder junction at about 2.550" COAL. That gives me a very small window for tuning. Right now I've found it's happiest at 2.560", but I expect based on some of the Mark Gordon jump research on this bullet, I expect it will be happier with more jump. I think I'm going to go to 0.230" FB.
Interestingly, I've heard two different gunsmiths say there should be a 0.100" FB difference between 105s and 115 DTACs. If the standard reamer is 0.120", that means a DTAC reamer should be about 0.220", which is right in the ballpark of where I want to be....
Any thoughts on this?
I'm in the lands at 2.590" COAL. I'm at the neck shoulder junction at about 2.550" COAL. That gives me a very small window for tuning. Right now I've found it's happiest at 2.560", but I expect based on some of the Mark Gordon jump research on this bullet, I expect it will be happier with more jump. I think I'm going to go to 0.230" FB.
Interestingly, I've heard two different gunsmiths say there should be a 0.100" FB difference between 105s and 115 DTACs. If the standard reamer is 0.120", that means a DTAC reamer should be about 0.220", which is right in the ballpark of where I want to be....
Any thoughts on this?
I agree with you. I've also read Mark Gordon's test results on that bullet. It seems to get the best results when started at about. 070 jump.
So if you want it to be seated above the juncture, you're going to need some freebore.
I'm pretty close to hauling my GT back out of the safe and reworking a load on it. I put it away because I shot it through some local stuff and 3 Pro Series matches in 100+ degree weather and it's been hard on it. I've lost .048 off the lands in 1500 rounds. I wanted to shoot it in the PRS Finale, so I put it away to save it for that. It's still shooting great, but my velocity has dropped from 2850fps to 2770fps.
I'm going to pull it out and use my 6mm throater to test some various freebore lengths. I'm thinking I'll test it at the .170'ish I'm at now, and then bump it to .200, then .220. I'm going to run loads on each of those to see what kind of velocity I can get before hitting pressure, all at .070 jump. It should be interesting. Hopefully I'll find something it really likes and have a better starting point when my new barrel shows up. This is my first 6GT barrel, its been a bit of a learning curve..
Thanks for the reply. Please share what you find here, and I'll do the same.
Are you running H4350? I've generally been only kinda impressed with the 6GT overall. I'm not sure if it's the freebore limitations, or the powder, of it's something else I'm doing. If I had a little Varget I'd try that and see if it behaves any better.... Shot the PRS Road To Redemption last weekend, shooting the Guardian at Pigg River next weekend, and then I think I'm going to cut the throat either 0.050" or 0.060" more and see how it behaves. I'm still not convinced whether my next barrel will be 6GT or 6BR/BRA.....
I've been running Shooters World Long Rifle in it with Hornady brass and CCI 450 primers. So a little outside the box. The burn rate is right there in between Varget and H4350. Closer to 4350 probably, as my load is 35.8grs to get an initial MV of 2850fps.
I'm also not ready to declare universal love for the round. I burned through close to 700 109gr Hybrids before giving up on them. I simply couldn't get them to shoot in this rifle. No idea why. I switched to DTACs and it immediately began shooting as it should. A short deviation to some 108gr ELDMs also resulted in a really good round. So that's a head scratcher.
I have no desire to run a lighter bullet in this round. If I were going to shoot 108's or lighter I would chamber up a 6BRA or Dasher. Its my humble opinion that the extra case capacity of the GT is best utilized running a heavier, higher BC bullet at the same velocities BR variants are running 105s.
But I like the DTAC. I shot thousands of them through my Creedmoor. My testing with the doppler radar via the Applied Ballistics team showed a very consistent .306 G7 BC on my rounds fired out to 1100 yards. The standard deviation of the DTACs ballistic coefficient was very low.
I want to like the 6GT, but it needs to fly right from here on out to win me over.
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Interesting to hear you use 0.306. I've been told my DTACs (which were purchased in late 2019 or so) are "the good ones". I've been using around 0.322 - 0.324 G7. (I use a 0.92 drag multiplier in 4DOF). That takes some of the sting out of the fact that anything faster than 2760 or so and the groups open up. I have not tested with any other bullets.
Your comment about losing 0.048" in 1500 rounds make me want to check where my lands are now... I'll have to test my throat tonight after this past match. I wonder....
I’ve been trying to try out some DTACs in my GT. Any idea where to get them or get on a waiting list? Thanks
I had a 500ct box of DTAC's saved in my cart their system didn't delete so I submitted it last weekend. They cancelled my order first thing Monday morning.
I think they are on hiatus indefinitely until Sierra gets caught up on everything else.
I have about 2200 of them. Not quite enough for the shooting season ☹
I have about 2200 of them. Not quite enough for the shooting season ☹
For anyone interested, David Tubb (SSS) has had 115 DTACs in stock on and off a lot lately. Apparently they're getting new lots every few weeks. I purchased another 2500 for my next barrel, and I can't wait to get them out to shoot them. And I've got nothing but good things to say about their customer service too - they're great to deal with!
I'll be shooting this batch out of a barrel with 0.220" FB - at least that's the current plan.
I'll be shooting this batch out of a barrel with 0.220" FB - at least that's the current plan.
I ordered 2k 115s 7 weeks ago, still awaiting shipment says the ups tracking number dtub sent after my order.
Ran 115s dtacs in a few local matches last two weekends. Yesterday the gun/myself shot well enough to get 1st place. 35.4gr H4350 running 2870fps 20k jump from a 28" 7.5tw, utilizing the 170 freebore alpha reamer. I personally feel a 200k freebore would be beneficial to a straight dtac dedicated barrel. Anything deeper than 37k jump looks to be pushing the bearing surface below nk shoulder junction.
AB custom curve was money at 2890 muzzle velocity trued at 1250y, validated from 400y to 1400y. Utilizing G7 bc at my known mv, 315 g7 held true to 400y-1100y, but 1400y required 310g7. Hornady 4dof, at known mv, form factor of 0.96 from 400y-1100y, but required 0.98 for proper elevation at 1400y.
One long range prone stage of day, 900, 1080, 1250, 1400, 1080 for 2 shots per target, 100% ipsc plates. Never dropped a point on this stage. They shoot great so far and were really easy to dial in. They shoot well at 2930 with another 1.1gr powder as well, but don't see the need as wind is only 0.1 mil different.
AB custom curve was money at 2890 muzzle velocity trued at 1250y, validated from 400y to 1400y. Utilizing G7 bc at my known mv, 315 g7 held true to 400y-1100y, but 1400y required 310g7. Hornady 4dof, at known mv, form factor of 0.96 from 400y-1100y, but required 0.98 for proper elevation at 1400y.
One long range prone stage of day, 900, 1080, 1250, 1400, 1080 for 2 shots per target, 100% ipsc plates. Never dropped a point on this stage. They shoot great so far and were really easy to dial in. They shoot well at 2930 with another 1.1gr powder as well, but don't see the need as wind is only 0.1 mil different.
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Glad you like them! Care to share the lot # and the best matching G7? I'm curious if the new batch is going to G7 as high as previous batches....
And yes, if I'm going to have a barrel for 115 DTACs, it's going to be more than 170 freebore.
Lot # is from May last year, I'm away from home at the moment. 52572 or something like that. I listed my BC findings in my post above.
