That’s .1 off a good Varget load for me... still need to explore more...
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Range Report 6GT Project/Range Report
- Thread starter NorCal Vu
- Start date
That’s .1 off a good Varget load for me... still need to explore more...
Run them again once barrel is done speeding up. The numbers are two inconsistent on either side of 34.4 at the moment.
Same here. Blamed it on everything under the sun. I had the same experience with multiple calibers. Definitely going to run hornady
So I jumped into the 6GT game...I have a Krieger standard palma 1:7.5 twist... not sure what reamer they used, but it is much longer than what everyone here seems to be running....with the Berger 105s I am getting 2.014 BTO touching the lands...seems most everyone else is around 1.95 - 1.98.... does this seem like the throat is too long?
BTO measurements are too varied from tool to tool.
OAL is much more indicative of a proper comparison.
Well I have a buddys gun here too and his BTO with same gages are in line with most on here @ 1.98 with the BERGER 105s
2.603 is my ave OAL
Might have a long throat as long as you’re measuring chamber correctly. I’d contact smith and get reamer print.
just start about .060 jump and go from there...ive seen 4 BRAs shoot great from .060 to .085 off the lands the last couple months.
Give this a read
precisionrifleblog.com
Load Development - PrecisionRifleBlog.com
These are the posts related to load development.
precisionrifleblog.com
Around 800 in and 34.6 varget is the sweet spot, consistent 3020MV on my 26” barrel. Buddy won a match with that same load on a 28” barrel, he’s sitting about 10FPS faster. I’m settling in on chasing .030” off, after every match I just bump out a couple of thou and that has treated me well so far.
How many firings you guys getting out of your Hornady brass? I’m sitting on a pile of 2x.Looks like they’re definitely good for more.
How many firings you guys getting out of your Hornady brass? I’m sitting on a pile of 2x.Looks like they’re definitely good for more.
Ya' know, if SH had the jerk award, guess who would win it?Why didn't you win a match with that load?
YOU!
Next match is a 2-day so hopefully, I worked out the kinks on this last one.
i'm 3 times through on most of mine and they're still fine. haven't even grown that much to were i need to trim them yet.
Nah, jerk award is club level. I'm definitely national level asshole.
I have to admit, I'm starting to get pretty frustrated with the GT. Between two barrels, one an Impact pre-fit and one a Bartlein chambered using their JGS reamer, I can't get anywhere close to the velocities people are claiming with 109s. Virgin Alpha, doesn't matter. Virgin Hornady, doesn't matter. Once fired Hornady? Nope. Once I start getting up past 2900 with 4350 or Varget, I get heavy bolt lift and other pressure signs. Might as well just run a BR.
How many rounds on the barrels? I've had better luck with RL16 than Varget or 4350.
that’s odd. Is the pre-fit from Impact themselves? I’m on my 2nd impact Pre-fit from Area 419. 1st one had about 350 rounds on it but had a groove in the chamber so I had to send it back. 2nd one has about 750ish now. 34.5 varget with Hornady brass and CCI 450’s have been the sweet spot for multiple bullets, both by myself and a few others I shoot with. 2950 with 109’s.
I will note that around 500 rounds I had a nasty carbon ring that started having pressure issues and 2 others I know had similar thing around the same round count area. Once I scrubbed that out it went back to normal.
2900 isn’t that bad honestly and will probably improve barrel life.
Yeah the one with 1000 on it is direct from Impact. The other is direct from bartlein though its not a profit.
I found a pretty decent node at 2860ish with H4350 and I don't mind running slow. Just disappointing when it's been advertised as a 2900-3000+ caliber.
Yeah that’s strange. Most of the people I see shooting it are around 2950ish with 109 and 110’s and 3000-3050 with 105’s. That’s with varget anyways. I found some decent nodes with RL16 and were a little faster but varget has just been accurate as hell with very low spreads.
@Darkside-Six the weird thing is that there are four of us regulars in my local club that are shooting GT and all of us are having issues getting it anywhere close to 3k without pressure.
Just started with a 6GT. All my previous 6mm's were .243s.
26" 7.5 twist Bartlein 5R HV
Tikka factory action and trigger
AICS 10 round steel mags (all fed smoothly)
KRG X-Ray chassis
Burris XTR II 8-40X-50
Vortex matched rings
EGW base
Area 419 Hellfire brake (not used for this testing)
Virgin Hornady brass 'mandrel sized' using just the expander stem in a Lee .243 Win. collet die (yes, I'm that cheap), and seating done with a Whidden micrometer die (but not *that* cheap
. I was pleasantly surprised by the Hornady brass. All 100 pieces were within 1.5 grains of each other (136 grain avg.), the untrimmed cases were 1.718 ±.002, and unsized headspacing was 1.353 ±.0005 (1x fired cases are showing 1.354 ±.0005 headspace and still ~1.718 trim length).
Used light (33.0 and 32.0 grains) of N140--fairly clean burning and close to Varget--behind some leftover 90 grain Nosler BTs and 95 grain Hornady SSTs for barrel break-in and rough 100-200 yard sight-in. Then used 37.0 and 37.5 of H4350 and 35.0, 35.5, and 36.0 grains of VV N150 behind 105 RDFs for 200 yard testing. All loads used CCI 450 primers.
I couldn't find any data on N150 for the GT, but knew it is closer to H4350 than it is to N140 and Varget in terms of burn rate. Still, even 35.0 is a bit too hot. No ejector marks, even at 36.0, but slightly stiff bolt lift on all and some light burnishing on the headstamps of a few. Flattened, but not cratered, primers. I have since done a face palm and looked at the VV N150 data for 6 Creedmoor, which tops out at 34.9 for the Hybrid Target and 35.8 for the VLD Target. D'OH! That's why it is called a *relative* burn rate chart.
Initial COAL/CBTO was determined by decreasing the seating on an empty case until I could gently, VERY gently, close the bolt, then seating ~.025 more (tested and inspected all loaded rounds to ensure no marking on the bullets). This worked out to:
2.450/1.962 Nosler 90 BT
2.405/1.930 Hornady 95 SST
2.540/1.960 Nosler 105 RDF
The target image is 200 yard testing of the H4350 and N150 loads (slight 3-5 mph head wind, ~90 degrees F, 80% relative humidity, near sea level, using a bipod and rear bag on a bench). Odd, but not unexpected, flyers with H4350 (due to the rough sizing/seating, not the powder, I'm sure), but okay results. N150 did a little better, but still a lot of room for improvement for both.
All should improve with 1x fired and properly sized cases, and some chronographing. If so, great. If not, then will be testing with N140, Varget, and Reloder-16. I have now drilled and tapped a fired case for my OAL gauge, and look forward to some proper seating depth testing. I also have a Whidden FL bushing sizing die and can test neck tension if needed, but I'm doing plenty of "foolish wand waving and silly incantations" to avoid having to turn case necks. I'd like to stick with the 105 RDFs if I can since they shoot great in my .243s and I have a LOT of them, but I also have some 108 ELD-Ms and some 115 RDFs. Will update ASAP.
26" 7.5 twist Bartlein 5R HV
Tikka factory action and trigger
AICS 10 round steel mags (all fed smoothly)
KRG X-Ray chassis
Burris XTR II 8-40X-50
Vortex matched rings
EGW base
Area 419 Hellfire brake (not used for this testing)
Virgin Hornady brass 'mandrel sized' using just the expander stem in a Lee .243 Win. collet die (yes, I'm that cheap), and seating done with a Whidden micrometer die (but not *that* cheap
. I was pleasantly surprised by the Hornady brass. All 100 pieces were within 1.5 grains of each other (136 grain avg.), the untrimmed cases were 1.718 ±.002, and unsized headspacing was 1.353 ±.0005 (1x fired cases are showing 1.354 ±.0005 headspace and still ~1.718 trim length).Used light (33.0 and 32.0 grains) of N140--fairly clean burning and close to Varget--behind some leftover 90 grain Nosler BTs and 95 grain Hornady SSTs for barrel break-in and rough 100-200 yard sight-in. Then used 37.0 and 37.5 of H4350 and 35.0, 35.5, and 36.0 grains of VV N150 behind 105 RDFs for 200 yard testing. All loads used CCI 450 primers.
I couldn't find any data on N150 for the GT, but knew it is closer to H4350 than it is to N140 and Varget in terms of burn rate. Still, even 35.0 is a bit too hot. No ejector marks, even at 36.0, but slightly stiff bolt lift on all and some light burnishing on the headstamps of a few. Flattened, but not cratered, primers. I have since done a face palm and looked at the VV N150 data for 6 Creedmoor, which tops out at 34.9 for the Hybrid Target and 35.8 for the VLD Target. D'OH! That's why it is called a *relative* burn rate chart.
Initial COAL/CBTO was determined by decreasing the seating on an empty case until I could gently, VERY gently, close the bolt, then seating ~.025 more (tested and inspected all loaded rounds to ensure no marking on the bullets). This worked out to:
2.450/1.962 Nosler 90 BT
2.405/1.930 Hornady 95 SST
2.540/1.960 Nosler 105 RDF
The target image is 200 yard testing of the H4350 and N150 loads (slight 3-5 mph head wind, ~90 degrees F, 80% relative humidity, near sea level, using a bipod and rear bag on a bench). Odd, but not unexpected, flyers with H4350 (due to the rough sizing/seating, not the powder, I'm sure), but okay results. N150 did a little better, but still a lot of room for improvement for both.
All should improve with 1x fired and properly sized cases, and some chronographing. If so, great. If not, then will be testing with N140, Varget, and Reloder-16. I have now drilled and tapped a fired case for my OAL gauge, and look forward to some proper seating depth testing. I also have a Whidden FL bushing sizing die and can test neck tension if needed, but I'm doing plenty of "foolish wand waving and silly incantations" to avoid having to turn case necks
. I'd like to stick with the 105 RDFs if I can since they shoot great in my .243s and I have a LOT of them, but I also have some 108 ELD-Ms and some 115 RDFs. Will update ASAP.Attachments
I have a GT that has about 1100 rounds on it with a 26" Proof 1/7.5 twist barrel. I run into pressure in the mid 2900's with both H4350 and Varget. I found a nice node just above 2900 and have been running it there for the time being. It hammers jumping the 109 .065, but I also feel like I should be getting more velocity before pressure.
I am having a bartlien 4 groove spun up shortly and will be interested to see what that barrel does. Both will be done with the same reamer and Smith.
I just measured throat errosion and I am at .018" after 1100 rounds with some PRS style shooting.
I am having a bartlien 4 groove spun up shortly and will be interested to see what that barrel does. Both will be done with the same reamer and Smith.
I just measured throat errosion and I am at .018" after 1100 rounds with some PRS style shooting.
what is your seating depth? I know with the hybrids they are not very jump sensitive but sometimes seating them a little deeper will eliminate that
Yeah that’s right where I am. .035-.040 and have had no issues but maybe pushing them further back will help.
You are focusing on the wrong thing. The gun hammers. Forget what the velocity is. It doesn't matter. None of the guys that are winning at prs consistently are running fast. Most are running very mild and CONSISTENT loads. There is very little reason to focus on the velocity. I will give you an example. My wife shoots a 6 Dasher at 2890 fps with a 105 Hornady HPBT. She is not a very serious competitor, but the gun is a hammer and will hold a waterline at 800 yds that is under an inch. It is uncanny. The wind hold for her load in a 10 mph wind at 1000 yds is 2.2 mils.
I shoot a 243ai with 115 DTACS at 3000 fps (also mild) because I see too many ro's not calling hits with the small 6mm calibers. My "hotrod windcheater" has a 1000 yd 10 mph wind hold of 1.6 mils in the same conditions. The difference looks to be significant, until you examine it through another lense.
A one mph wind error will make the 6 dasher miss by .22 mils and the 243ai misses by .16 mils for a difference of .06 mils between them. The difference is 2.16" at 1000 yds. Both shots stay inside of a 2 moa target. Extend the error to 2 mph and both miss a 2 moa target.
The next part is what most people miss. I struggle to get my gun and load to hold 3-4 in of vertical at the same 800 yd target. With the Dasher it is automatic. Just about any reasonable load is at or under 2" of vertical at 800 yds. There is much less vertical uncertainty which makes every circle and diamond target wider.
The differences are even smaller when choosing between the high node and the low node for a particular cartridge. The example above was extreme in that the faster velocity was also with a bullet that has a g1 bc that is 17% higher than the bullet being utilized in the slower cartidge.
Running the low node will extend barrel life and eliminate problems in rainy or dirty conditions that arise from pressure. Brass will also last longer.
The only time it makes sense to push a cartidge is in elr applications or when there is range uncertainty. Neither of those exist in a typical prs match that the 6 gt was designed for.
After thinking about it in this manner I am convinced there is little need for large hotrod cartridges or chasing speed for prs shooting. This is especially true if hit indicators are used on targets. It makes more sense to shoot a cartridge with good accuracy potential that is easy to load for and has decent barrel life. Running the low node will help far more by being less finicky, extending brass life, and preventing issues from pressure in rain. Running the high node chasing velocity makes one vulnerable to all of these potential issues.
Just my $0.02 worth when it comes to chasing velocity.
I think it’s more of a principle thing. Cartridge was advertised to get to X speed and is only getting Y speed.
Seems to be a fairly common complaint. The reason could be operator error, but if so, there’s a lot of operator error happening as there a lot of people reporting similar issues.
I would have to agree with everything you said 100%, thats why I'm not too upset about not achieving the higher velocity. In all reality, 75-100fps is really not doing anything for me. On the other hand, the cartridge was marketed as being 3000+fps capable, and I am finding quite a few people have trouble getting there. I am also at almost 0 elevation and its been 90 degrees out, so I'm sure that has an effect on pressure.
I just did a seating depth test today after erroding the throat .018 before changing seating depth, and now the gun seems to like.the .030-.040 jump. Regardless, im not going to complain about the performance right now, was just makimg observations.
I certainly understand that sentiment. I think just about every cartridge is promoted excessively and touted as the next game changer right after they are created and released. Once you've messed with a few of them it starts to become obvious that there are no free lunches and every cartridge is a tradeoff of sorts. There are a lot of variables even with the same cartridge. People that have different use cases for the same cartridge often report wildly different results.
I think the 6 gt is a fine cartridge, but I don't see it as anything groundbreaking. They (basically) took a 6 Dasher and lengthened it to make it feed from magazines more reliably. I'm not surprised to see that the velocity is similar to the Dasher, regardless of what was touted by the promoters.
Even given the above, I understand the frustration when things are over promised and under delivered.
I'm running ARC w/LRI followers, MDT 12 rd, Alpha and AI without any problems. I had to cleanup the edges of the ARC mag feed lips with some sandpaper.
Thank you. I have a selection of magazines MDT 12, AICS, Magpul AICS... etc. I've read that it is finicky. Would you mind measuring the front rear and middle of your feed lips on the MDT 12's?
What ever they were from the factory. I haven't touched them. Some of it has to do with mag height in the stock/chassis. The newer MPA have an adjustable mag height.
Hello all... I actually had some feeding issues this weekend with my GT and a bit confused running a poly mdt 10 rnd in a bighorn origin. It was good for the first couple of rounds then would t pick up the next. A smack to the bottom and it would catch. Any suggestions?
That’s what I was thinking was good and tested after your post. Tension and push to the feed lips looks good but on a 10 round mag after cycling the bolt 7 rounds I would get a failure to feed. Did that about 10 times and it was pretty consistent on the 7-8th round it would fail.
I’ll try a metal mag and see. Any suggestions? 12 rounders?
I run the MDT poly mags with the metal feed lips and I have had zero issues in an MDT ACC chassis and Curtis vector action. They are only 10 rounders though. It looks like you could put an extension on it if you wanted to, but I haven't even looked into it. I actually prefer them without an extension just because I don't like the extra length in the magazine and have never had an issue sled loading or just swapping mags on a position change.
That’s what I was thinking as it’s a pressure / tension Issue. Either a spring issue or the feed lips. The mag I’m using now is the poly feed lips so I need to try metal.
While I applaud and respect George for all he's done for the gun community, and his inventiveness for coming up with new cartridges to benefit our segment of the community, he does have a little bit of a habit of overselling the cartridges he brings to life.
I'm not sure if that's over optimism or a bit of a sales pitch on his part, but those that look at the history of his cartridges should expect to be a bit more conservative on all figures from what he advertises.
I agree
I'm starting to think that 2800-2900 is all im going ro get out of the cartridge running A-tips and 4350. Im fine with that as long as I get decent barrel life.
@reubenski
Hornady Virgin brass
36.5 of H4350 (2820)
37.0 of H4350 (2850)
Hornady 110 A tips at 0.050" off
CCI450 primers
Neck tension set with a K&M 0.004" mandrel.
I might try to go back to 0.030" off the lands before the next two day match but we'll see
Hornady Virgin brass
36.5 of H4350 (2820)
37.0 of H4350 (2850)
Hornady 110 A tips at 0.050" off
CCI450 primers
Neck tension set with a K&M 0.004" mandrel.
I might try to go back to 0.030" off the lands before the next two day match but we'll see
