Maybe your mag isn’t positioned optimally with your chassis/action combo? Do you have a lot of for/aft wiggle?
6gt
- Thread starter Dthomas3523
- Start date
Hmmm maybe I'm reading it wrong, but 1.725" - 0.020" = 1.705"? That is 0.015" shorter than the 1.72" trim length in Hodgdon data. Or do you trim to 0.01" under max?
I worded my post incorrectly, the max length is .005 longer than what was originally put out. I've never looked at hodgdon's information. Originally it was 1.720 - .010.
On my 4th barrel. 2 back-to-back matches next month to burn her in. So far, so good. Dropped some speed on a new jug of Varget.
Get ahold of MDT. They reached out and sent me new followers, mag springs, and spacers to alleviate the issues I was having. Make sure you tell them if you have binder plate or non binder plate mags. Also, let them know if you have 10 or 12 round magazines. They will send the proper sized spacer for them.
The only downside so far is that I have to load to mag length and under to find my optimal seating depth. This knocked off about 60 thou of play room off the lands for me.
Attachments
I'm not sure how to continue to be polite and say I don't run MDT mags in my GT because they don't fvcking work.
AI Mags, ARC mags, take out of package, insert bullet, go to range.
Rinse, repeat.
No calls. No email. No swapping. No tweaking feed lips. No searching who else has the problem.
Apologies in advance for jumping from the current topic on this cartridge.
Anyone have experience running 115 DTAC's? Just fire formed cases and about to get into load development.
HH barrel (7.5"twist)26", Alpha brass (current GEN), GMM primers, H4350. I want to be able to compete at 1k with this cartridge. I haven't chrono'd anything to this point. From what I can see, the 105 to 108 grainers seem to be the best performers to this point.
I guess I'm wondering if the 115 is simply too heavy. F-Open is the disclipline.
I could always designate these for 600 matches only. Just wanted some feedback from those who've gone the 115 DTAC route? Thanks
Anyone have experience running 115 DTAC's? Just fire formed cases and about to get into load development.
HH barrel (7.5"twist)26", Alpha brass (current GEN), GMM primers, H4350. I want to be able to compete at 1k with this cartridge. I haven't chrono'd anything to this point. From what I can see, the 105 to 108 grainers seem to be the best performers to this point.
I guess I'm wondering if the 115 is simply too heavy. F-Open is the disclipline.
I could always designate these for 600 matches only. Just wanted some feedback from those who've gone the 115 DTAC route? Thanks
DTACs will work fine for the 6GT.
They have some inconsistencies in the past, but it may have been fixed.
They have some inconsistencies in the past, but it may have been fixed.
That may be for you, but I have had zero issues with 5, 10 and 12 round MDT mags. I have some shooting buddies that use AI mags and they’ve modified them to suit their needs. They modified the feed lip angles and cut the lips shorter.
I have used other mags in another gun and had to modify the lips to feed. I did what was needed to make them run.
I don’t think it’s as easy as saying they never work or always work. There are so many combinations of cartridges, actions and chassis/stocks that no one brand is the end all be all.
I’ve been shooting GT pretty much since it’s inception. I’ve always ok h ever used AI and Accurate mags. I’ve never had any issues with them feeding. Coincidently, pretty much everyone I do see having feeding issues are all with MDT mags. Just sayin 
A lot of issues can be traced to the bottom metal or chassis, in some cases. In my experience, I have used Magpul, ARC, AICS, AW, and MDT mags for multiple barrels. The only issues I had were associated with a Gen 1 and Gen 2 Manners Mini chassis. I have had zero issues over many barrels with Hawkins or OTM M5 dbm.
I'm sure some are, but my mag issues aren't bottom metal related. I'm using an MDT mag in an MDT chassis, but I can see the top round nose diving just holding the loaded mag, when I strip one off either with the bolt or by hand, it will do the same thing until I get down below 8 rounds in the mag. I didn't notice earlier because I was only loading 5 for most of the load development. Messing with feed lips hasn't really helped yet, it seems like friction in the mag body is keeping the top round from pushing up against the lips sufficiently, and I've cleaned the mag with one shot, which usually slicks things up pretty well.
Seems like the reviews have been mixed on ARC mags feeding reliably, maybe Accurate would be a safe bet to try next.
I've only used accurate mags and they feed without any tweaks
Accurate-Mags work well for me in a ACC Chassis. Still had to open up feed lips slightly for smoother feeding.
Not to beat a dead horse, but...
Like most everyone else, I had trouble feeding 6GT with MDT mags. I was not surprised as it was a known issue when I started shooting the cartridge. I asked MDT about it and this was the response:
In my experience, no amount of feed lip tuning will completely resolve the issue without creating another issue. The Dasher/BR mag kit will limit your OAL to 2.505" which is way to short for me (standard freebore).
Accurate mags work fine, but did require some minor tuning to feed smoothly in my case.
Like most everyone else, I had trouble feeding 6GT with MDT mags. I was not surprised as it was a known issue when I started shooting the cartridge. I asked MDT about it and this was the response:
In my experience, no amount of feed lip tuning will completely resolve the issue without creating another issue. The Dasher/BR mag kit will limit your OAL to 2.505" which is way to short for me (standard freebore).
Accurate mags work fine, but did require some minor tuning to feed smoothly in my case.
+2
I spent a lot of time trying to tune my MDT mag and it just wasn’t there. I had 4 and 2 ran fine, 2 did not. All 4 purchased at the same time. I hit them up and got a dozen questions, I’m like but 2 are good and 2 are not… I don’t quite think it’s the chassis or action.
I ended up shifting to accurate and they ran my GT fine.
I tried the plastic MDT mags and they absolutely did not work for my GT. However a friend has used them and had no issues… we run the same chassis and action.
Oddly I had similar issues with MDT and their BR mag. Some worked and some simply did not.
The accurate mags are actually cheaper than MDT mags now. Natchezs has them for $63.
I have run nothing but arurate mags and I haven't had to mess with a thing
Part# 1000040 = no binder plate - max OAL 2.950"
Part# 1000009 = with binder plate - max OAL 2.875"
I use the mags with the binder plate and haven't tried without. I have friends who prefer the no binder plate version. I am not sure if it makes a difference for 6GT because I don't think you can load it beyond 2.875".
Both are 10 round mags that will only fit 10 round of 6GT.
Part# 1000009 = with binder plate - max OAL 2.875"
I use the mags with the binder plate and haven't tried without. I have friends who prefer the no binder plate version. I am not sure if it makes a difference for 6GT because I don't think you can load it beyond 2.875".
Both are 10 round mags that will only fit 10 round of 6GT.
The following data collected at 1,400 rounds on a 26" Benchmark VCC. Velocity has slowed substantially, which could be due to a variety of factors including throat erosion, brass prep, different lot of powder, weather, etc. These are 5 shot sample sizes. I ended up running 32.9 gr which averaged 2,830 FPS over a larger sample size.
Berger 105 gr Hybrid
Varget (32.2 gr to 33.4 gr)
CCI 450
GAP Hornady Brass (3x fired)
+/-0.060" jump (1.919" CTBO)
26" barrel, 1:7.5" twist
Temperature: 57
Humidity: 25%
Pressure: 27
32.2 gr Varget
Ave MV: 2,785
ES: 30
SD: 12
32.4 gr Varget
Ave MV: 2,793
ES: 34
SD: 14
32.6 gr Varget
Ave MV: 2,809
ES: 12
SD: 4
32.8 gr Varget
Ave MV: 2,819
ES: 22
SD: 9
33.0 gr Varget
Ave MV: 2,833
ES: 16
SD: 7
33.2 gr Varget
Ave MV: 2,857
ES: 26
SD: 12
33.4 gr Varget
Ave MV: 2,875
ES: 37
SD: 18
Berger 105 gr Hybrid
Varget (32.2 gr to 33.4 gr)
CCI 450
GAP Hornady Brass (3x fired)
+/-0.060" jump (1.919" CTBO)
26" barrel, 1:7.5" twist
Temperature: 57
Humidity: 25%
Pressure: 27
32.2 gr Varget
Ave MV: 2,785
ES: 30
SD: 12
32.4 gr Varget
Ave MV: 2,793
ES: 34
SD: 14
32.6 gr Varget
Ave MV: 2,809
ES: 12
SD: 4
32.8 gr Varget
Ave MV: 2,819
ES: 22
SD: 9
33.0 gr Varget
Ave MV: 2,833
ES: 16
SD: 7
33.2 gr Varget
Ave MV: 2,857
ES: 26
SD: 12
33.4 gr Varget
Ave MV: 2,875
ES: 37
SD: 18
Breaking in my barrel. 35g H4350, 108 BT .0020 off the lands, CCI 450s, Alpha OCD virgin brass. Groups have been very good. ED/SD are all over the place. From 8/3.6 to 43/16.7. I'm at 100 total rounds fired and no signs of speeding up yet. What kind of change in FPS should I expect to see when it begins to speed up? Is it incremental over a period of rounds? Or does it just get faster over several rounds?
2805 avg. 24 ED/ 10.6 SD
2805 avg. 24 ED/ 10.6 SD
I'd break in 36.5gr of H4350 with Alpha brass. One of the nice things about 6GT is there's pretty much no reamer variations. I'll wager you final charge weight will be around 36.7gr going 2900fps using Alpha brass.
Have you found it easy to get low SD’s with H4350 in the GT? Does it have a wide node?
I'm about ready to go load 50 rounds to shoot tomorrow for more break-in. Rounds 101-150. I'll vary some load weights and work up to your recommendation quickly and see how it goes. Hopefully we'll see her speed up a bit and I can 'try' to get some load development done for Raton next Sunday. Thanks for the recommendation.
GT is probably one of the most forgiving cartridges to load for. Super easy.
2 different 6gt barrels, not as easy as a dasher, bra, or br, but def not picky. 36.6gr H4350 with 109s 40k off lands shoots 4" at 870y thats the furthest I've shot paper. I think last time i ran 15 over chrono I had an es of 13, avg was 2907fps. I'm running a 28" bartlein 7.5tw.
Again, 6GT has almost no reamer variations. Follow this guy's load:
36.5gr to 36.8gr of H4350. 105gr to 109gr projectiles. .030 to .050 off the lands. Painless.
Here is a little more powder/velocity info for folks.
Alpha brass (1x fired, no shoulder bump)
CCI BR4
Bart's 105 Gungnir
30 inch 8 twist Blake barrel
VARGET
33.2 - 2960
33.5 - 2972
33.8 - 2995
34.1 - 3003
34.4 - 3024
34.7 - 3051
35.0 - 3074
35.3 - 3092
35.6 - 3119
35.9 - 3136
H4350
36.5 - 2975
36.7 - 2974
36.9 - 2982
37.1 - 3001
37.3 - 3016
37.5 - 3023
37.7 - 3040
37.9 - 3053
38.1 - 3072
38.3 - 3091
Hope this helps!
Alpha brass (1x fired, no shoulder bump)
CCI BR4
Bart's 105 Gungnir
30 inch 8 twist Blake barrel
VARGET
33.2 - 2960
33.5 - 2972
33.8 - 2995
34.1 - 3003
34.4 - 3024
34.7 - 3051
35.0 - 3074
35.3 - 3092
35.6 - 3119
35.9 - 3136
H4350
36.5 - 2975
36.7 - 2974
36.9 - 2982
37.1 - 3001
37.3 - 3016
37.5 - 3023
37.7 - 3040
37.9 - 3053
38.1 - 3072
38.3 - 3091
Hope this helps!
Hey guys, i am building a 6gt bolt gun and was wondering what powder you’d start with out of bl-c(2), 4895, xbr 8208?
I have br-4 and 450 primers, alpha brass, and 108 bergers, i also have some Varget but not much. I been keeping an eye of for h350 but haven’t been able to get some yet.
I have br-4 and 450 primers, alpha brass, and 108 bergers, i also have some Varget but not much. I been keeping an eye of for h350 but haven’t been able to get some yet.
Any Varget class or H4350 class will work in the GT. Look for 4166, 4451, Staball, CFE223, RL15, 15.5, 16, 17 Whatever VV equivalents are and so on.
Last edited:
Well there you go. I did five round strings starting at 35.0 going .2 each string except when I got to 36.4 I went to 36.5 then 36.6. They all did pretty good except 35.0 and 36.6.
Of course it was the worst group of the bunch. I just loaded 50 rounds at 36.5 and varying seating depths from .001 to .005 at .001 increments. But honestly, even the bad ones were probably better than most of my 6.5CM loads.
Keep coming with the advice because I can't take credit for this. Thanks for the hint.
Well there you go. I did five round strings starting at 35.0 going .2 each string except when I got to 36.4 I went to 36.5 then 36.6. They all did pretty good except 35.0 and 36.6.
View attachment 7817905
Of course it was the worst group of the bunch. I just loaded 50 rounds at 36.5 and varying seating depths from .001 to .005 at .001 increments. But honestly, even the bad ones were probably better than most of my 6.5CM loads.
Keep coming with the advice because I can't take credit for this. Thanks for the hint.
I'm using berger 109Hyb so my results are probably going to be different but most user loads I've seen posted are .030 to .050 off the lands.
I am running 108s too. They did very well at .040 to .060 off lands.
My experience with the 109 hybrids across 3 barrels was .060 - .080 is where the sweet spot is. They’re not real jump sensitive but that’s is where they really tightened up for me.
108bt ran very well 10 and 20 off in a prior barrel, like stupid good. 1.5" 10 shot groups at 500y. Was running rl16 @ 2940fps.
Yea, trying to get slower velocity. I have one bbl that is just really fast. Same load on my other bbls and it's about 100-120fps faster.
I primarily use H4350. But seems like it needs good case fill for lower SD/ES. I have RL23 for use with my 6.5PRC (Barnes 127LRX) and may give this a try.
Same base to ogive seating depth I've been running(-40) with 109s for 700 rounds. Barrel has just over 1400 on it. H4350 36.5(warm temps), 36.6(med temps, 36.7(cold temps) keeps speeds right at 2900. This was the cold weather ammo shot at 50° today, avg velocity was 2912 with es of 20 over 25 rounds fired. Same ammo shot 1.5" at 400y but didn't feel like hiking back up the snowy hill to fetch target. 50° and snow on the ground with swirly winds had pretty heavy mirrage, so groups may have been better in ideal conditions. Barrel is a BB steel bartlein 7.5tw 237 bore 28" hvy varm. This is what a person looks for in a prs load, super stable over the course of 700 rounds fired. I'm unsure of throat erosion as this point as I haven't checked since it just keep shooting. I just adjust the charge weight by 0.1 for different seasons as I'm not in a powder node, but the speed node of 2880-2910 held excellent vertical at 500y upon initial ladder. Last fall this velocity printed 4.7" group at 870y. All shooting is from a bipod and rear bag field conditions, no benchrest bs.
It liked .10 today. But I got better SDs/EDs at .50 and was just a little tighter. But after reading above, it looks like I need to push a little farther to see.
I had a roll going until the 5th round. It read an SD of 0.0 right before shot 5. My panties got a little moist and I think it slowed down shot 5.
