Hey guys, I'm having trouble getting the 115 DTAC RBTs to group, so here's the info on the gun and what I've tried so far. Shooting them from a 7 Twist 26" MTU Criterion prefit in 6 Creed mounted on a TL3. Broke in the barrel til speeds started settling down and then did load development and node with a load of H4350 in Peterson SRP brass with CCI 450s that gives me 6fps SD at around 3030fps but the groups on paper are awful, not even 1 MOA. Tested seating them 10, 20 and 30 thou off the lands and they seemed to like 10 best but still bad groups. Cases are all fired in my chamber, annealed and set back 1 thou, bullets are seated using a forster ultra mic and not using a compressed load, all primers are hand seated and anvil pre-stressed. I've run out of potential sources that I can think of, any ideas? (Ladder tested some 108 ELD-M in the mean time and the whole ladder group was smaller at 100 yards than my DTACs, i just hate to ditch 400 bullets)
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Why can't I get DTACs to group
- Thread starter Mnash
- Start date
As found in Berger suggestion:
Solution
The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a COAL that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands.
Note: When discussing jam and jump I am referring to the distance from the area of the bearing surface that engages the rifling and the rifling itself. There are many products that allow you to measure these critical dimensions. Some are better than others. I won’t be going into the methods of measuring jam and jump. If you are not familiar with this aspect of reloading it is critically important that you understand this concept before you attempt this test.
Full article is here: https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
Solution
The following has been verified by numerous shooters in many rifles using bullets of different calibers and weights. It is consistent for all VLD bullets. What has been discovered is that VLD bullets shoot best when loaded to a COAL that puts the bullet in a “sweet spot”. This sweet spot is a band .030 to .040 wide and is located anywhere between jamming the bullets into the lands and .150 jump off the lands.
Note: When discussing jam and jump I am referring to the distance from the area of the bearing surface that engages the rifling and the rifling itself. There are many products that allow you to measure these critical dimensions. Some are better than others. I won’t be going into the methods of measuring jam and jump. If you are not familiar with this aspect of reloading it is critically important that you understand this concept before you attempt this test.
Full article is here: https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/
I know this is pretty common for bergers and other VLDs, but the DTACs are a tangent ogive and shouldn't be picky like a secant, or at least in theory. I asked a fellow shooter who is successfully using the DTAC in the same cartridge and he reported success at 20 thou, it's hard to believe it would be that far off, but maybe I'll have to give it a try. Thanks for the suggestion!
They shoot great out at distance! a true .620 BC with no correction required when I trued them, but the KYL stages kill me when I have to shoot little targets.
I am running pretty much the same barrel with the DTACS jumping .020, 40gr H4350, lapua brass, CCI450, .002 neck tension. 3010fps, SD of 5-6. The accuracy node was ridiculous 39.5-40.5 all shot a ladder test into a group that measured .5 moa. Maybe your barrel just doesn’t like them.
I've had quite a few loads group shitty at the highest node, and get into focus great with the next or the following slower one.
I couldn't get them to group with H4350. Switched to H1000 and they were instantly better. Used the same methods of loading everyone else seems to use.
Just food for thought.
Just food for thought.
I just shot some for the first time. Best grouping was at 37.9 gr of H4350. Getting half moa, and smaller with that load. Fps is at 2858. Using proof barrel, 1/8 twist
Try a 10 thou jamb or a bigger jump. The first Criterion barrel I did load development for I just found the lands and turned the seating stem to what I thought would be .040 off. It ended up at .037 off and I just shot it. It shot under half moa for most of the loads in the test until I saw pressure. I never chased the lands and at 2500 rds the barrel started throwing random fliers. The new barrel I tested .010 in, .010 off, .040 off, and .080 off before working with ladder testing. The first three all shot well, but .010 off shot the best. After finding a charge weight I liked I tested more and found .020 off to be a little more accurate, but again everything from .010 off to .025 off shot really well, right around half moa. I would explore a different charge weight. I can't be much help there as I have been shooting them in a .243AI. If nothing shoots better I would ditch them and try a different bullet.
One thing to think about is sometimes a good load on the chronograph isn't the best load. Both of my loads had shit sd and es but held vertical really well at 800 yds (the furthest my range has to test) I know as I get further out I will start to see the dispersion, but I never had troubles hitting to 1000-1100 in matches. At 800 the loads will shoot 2-2.5 inches of vertical for 10 shots, but the SD is in the high teens to low twenties. I didn't know that until I had already tested extensively and strapped the chronograph on to get the mv. I decided it was always fine before when I didn't have a magnetospeed. The only difference now is that I know the results. I see people post that they have success at 1000 yd br with loads that have mediocre sd and es as well. Good luck. I hope you can get something worked out. It is frustrating to have a bunch of stuff sitting around that doesn't shoot well.
One thing to think about is sometimes a good load on the chronograph isn't the best load. Both of my loads had shit sd and es but held vertical really well at 800 yds (the furthest my range has to test) I know as I get further out I will start to see the dispersion, but I never had troubles hitting to 1000-1100 in matches. At 800 the loads will shoot 2-2.5 inches of vertical for 10 shots, but the SD is in the high teens to low twenties. I didn't know that until I had already tested extensively and strapped the chronograph on to get the mv. I decided it was always fine before when I didn't have a magnetospeed. The only difference now is that I know the results. I see people post that they have success at 1000 yd br with loads that have mediocre sd and es as well. Good luck. I hope you can get something worked out. It is frustrating to have a bunch of stuff sitting around that doesn't shoot well.
I get that rifles can group with bad sd and es velocities but it's not advisable to knowingly settle for and load as such. If you can get another bullet to run easier you may just want to go that route for the sake of barrel life.
Some local shooters in my circles have reported problems with the DTACS not shooting well as of recent. Some of them went to the Barnes match burner 112's and are having good success with them.
Nothing against the DTACS on a personal level, years ago they were my go-to, and they worked fantastic at the time.
First, post some pics of this grouping. They can tell a story, is your problem vertical or horizontal, or scatter node.
I still believe you control vertical with charge, horizontal with seat depth. It sounds like you are new to the dtac, try to tighten your groups horizontally by messing with the seat depth, it is easy to do. Then concentrate on finding a charge that holds vertical, I am assuming you are doing all this at 100 yards. Can you take your press, die, and caliper to the range, if so, seat bullets long, start 6 off and work in .002" increments. If you know you are taking good shots and it is not looking pretty, move on, if you know you biffed a shot in a string, seat another same depth. If you find something, repeat it. Then work on your powder charge.
Not busting your balls, but why switch bullets before trying a diff powder first? You are not exasperating your options if you truly want to shoot the dtac. Dtac is heavy for caliber bullet, with a fair amount of bearing surface, maybe a slower powder is in order.
I shoot these in my 6x47 Lapua and everything I have shot for load development has been so good it is hard to settle on something so I went with lowest ES /SD. My load is 39.2 of H4350 .020 off the lands. For me in prone was .5 MOA load.
I also found that they seemed to be very jump tolerant like a SMK.
David
I also found that they seemed to be very jump tolerant like a SMK.
David
Try slowing it down a bit. I run mine at a pedestrian 2900 with rl16, and it’s effortlessly accurate.
The above rifle shoots the dtacs in any combo. There is no sweet spot. Jump doesn’t matter, charge doesn’t matter, it always groups. Last week I substituted h4350 at the same charge weight just for giggles, and it shot identically. And on that note, if the barrel just doesn’t like them, take the hint and move on. Seems a long shot to me that it’s gonna clean up with a few thou of seating depth, or a charge adjustment. Do you really want to deal with such a finicky load?
As a general musing, how many “my criterion won’t shoot” threads have there been in the last few weeks?
The above rifle shoots the dtacs in any combo. There is no sweet spot. Jump doesn’t matter, charge doesn’t matter, it always groups. Last week I substituted h4350 at the same charge weight just for giggles, and it shot identically. And on that note, if the barrel just doesn’t like them, take the hint and move on. Seems a long shot to me that it’s gonna clean up with a few thou of seating depth, or a charge adjustment. Do you really want to deal with such a finicky load?
As a general musing, how many “my criterion won’t shoot” threads have there been in the last few weeks?
Other than the criterion may not have been the premium choice, nothing you said here makes any sense to me. Loads rarely fall into your lap, finding a load for a rifle is simple if a few protocols are followed. There are many methods out today that seem satisfactory, and the OP was vague on his methods used. By his emphasis on SD numbers, I assume his node was found with a chrono.
We all have differing degrees of accuracy we will settle for, and all bullets will have a better seating depth if time is taken to find it. No different than the powder charge, you find a charge that holds vertical at distance, you are 80% home.
I don't care for people complicating the shit out of things, but simplifying it really doesn't do anyone any good either, unless being satisfied with mediocre is the game.
Milo, he’s shot enough rounds to get past the barrel speeding up, and done a range of seating depths. Certainly he must have traversed a range of velocities. Even if his methodology totally sucked, he should have some good groups to show for it. Some zone where things look better than the rest. He even mentioned doing a 108 eld ladder(apparently he knows how to do that) where the whole ladder produced a smaller group than his DTAC loads. That should be a pretty big clue for him.
In my experience, good quality barrels tend to shoot well. I’ve owned dozens and dozens of them, and I can only think of a few that I had to work at. This thread is gonna go two more pages, his method will get completely revamped, he’ll burn through the 400 remaining dtacs chasing suggestions, be halfway through his barrel life, when he could’ve just shot 108’s. The dtacs don’t have an expiration date, and the OP can give them a whirl on the next barrel, which hopefully will be a Bartlein or Krieger.
In my experience, good quality barrels tend to shoot well. I’ve owned dozens and dozens of them, and I can only think of a few that I had to work at. This thread is gonna go two more pages, his method will get completely revamped, he’ll burn through the 400 remaining dtacs chasing suggestions, be halfway through his barrel life, when he could’ve just shot 108’s. The dtacs don’t have an expiration date, and the OP can give them a whirl on the next barrel, which hopefully will be a Bartlein or Krieger.
Lol, lot of truth there.
I myself would die with my choice though, I've never had a bullet I could not get to shoot, some took time, and money, and frustration. Now I have shot a bullet for 4-500 rds and said screw this pile of shit after continually adjusting seat depth to make it shoot.
My 6mmFatRAt hates 105 hybrids?? but loves 95smk, that surprised me.
Tried some 105 RDF's in my 6MMBR, shot okay at 100Y, a flyer here and there, same at 300Y, even had some 3/4" groups at 300Y. Horrible vertical at 1000Y, 3 feet.
Had a 375ct barrel that wouldn't shoot but moa at 100Y with Hooker tactical 350gr but by 400Y would shoot 2.5" and kept it up farther out. 2-3" groups at 100Y with 350 smk??!!
Out of 10 or so barrels these were the only weird experiences, other than a worn barrel i've had for 10 years that fouls up gives some grief but shoots well if it's cleaned again. Borrowed time...
Tried some 105 RDF's in my 6MMBR, shot okay at 100Y, a flyer here and there, same at 300Y, even had some 3/4" groups at 300Y. Horrible vertical at 1000Y, 3 feet.
Had a 375ct barrel that wouldn't shoot but moa at 100Y with Hooker tactical 350gr but by 400Y would shoot 2.5" and kept it up farther out. 2-3" groups at 100Y with 350 smk??!!
Out of 10 or so barrels these were the only weird experiences, other than a worn barrel i've had for 10 years that fouls up gives some grief but shoots well if it's cleaned again. Borrowed time...
I think you may just have a barrel that doesnt like dtacs. It sounds like you have tried a lot to get them to work. If it shoots something else better, shoot that bullet. If you really want to shoot dtacs get another barrel. You may eventually find a load with dtacs that shoot in it but you may have burnt out the barrel by then. I don't think it is because it is a Criterion instead of Bartlein, etc. I have a Criterion that shoots as well or better than my Bartlein, but sometimes you get a barrel that either doesnt like a certain bullet or occassionally just doesnt shoot at all. I would shoot the 108s and either sell the dtacs or save them for next barrel.
I would dump the DTAC and shoot the 108 if they shoot good. I have been through three lots of DTAC bullets. The first two where excellent. .3-.4 moa was easy off a bipod with a rear bag. The bc trued to .620 or maybe even should have bumped it a smidge higher to get things to true up at distance. Very little load development to get there and everything in load development was under .4 and some in the .2 for 3 shots. This was a criterion. Fast forward a season to another criterion (same exact specs a previous), now Hornady 105 HPBT shoots tighter up close than the DTAC although the DTAC do still hold right at .5 moa. This new lot of DTAC bullets they attempted to point, but the meplat isn't closed. Like the pointing die wasn't set up correctly or the jacket was too short. Also, the edge of the RBT is not as crisp as any of the other lots and is more rounded. The BC on this lot and this barrel true out to .585 and I can tell they aren't stabilizing as well because the bc gets worse as the temp drops when the stability factor is still 1.35-1.4 where the old lots didn't show this until the calculated sg was down to 1.1-1.15. So many things changed at once that I can't say if it is the bullet or the barrel. I know other people have brought this up in the past with the noses not being closed. They still shoot really well for me, but they definitely aren't as good as the other two lots I had. On a positive note, Tubbdust mixed with H1000 is pretty nice.
The reason I went with a criterion prefit rather than a Bartlein or the like is that I'm shooting a lot of matches, and when you burn through a 6 creed barrel in 12-1500 rounds that just gets too pricey for me. I'm not trying to shoot benchrest or break any records and prefits have shot fine for me so far. As far as my load development methods, I have been using a modified version of scott satterlee's chronograph load development. Rather than just shoot 10 rounds I shoot 30, 3 of each charge weight in .2 increments, over the chronograph and then plot all the results in an excell graph I got from the 6.5 guys. It gives a good visual representation of your velocity flat spots and best ES / SD loads. I then pick out a couple nodes and retest those over the chrono to confirm, this time on paper as well to check out the groups. I don't shoot on paper initially because I know that my shooting ability is the weakest link and I don't want to bias the testing. It's more important to me how they shoot at distance (ES) than how they group at 100, although I still need something tolerable for those KYL stages, and I figured I could adjust seating depth to get the load to group
Sometimes adjusting seating depth in .005" increments I will see a noticeable change in group size and shape with one adjustment. Padom suggests testing in .003" increments. I have not seen this with DTACS specifically, as they tend to be pretty forgiving, but they do typically tune to a tighter, more round group when you get to a good seating depth. My experience with DTACs though is that everything shoots tight at 100 until overpressure. Some loads just shot tighter than others.
