Ok good that you are not having the issues I was with the custom Bartlein Barrel kit I have. Mine would not chamber on new factory RWS brass without being sized quit a bit.Yes..
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390 grain Hornady A-Tip load development 375 Cheytac
- Thread starter secondofangle2
- Start date
that cloud does have a silver lining. The quantity of .50 powder that I bought (enough to burn out 2+ barrels) can be used for 390 grain ATIPs.
Are you going to try H50BMG or stick with RL50?
If I come across a pound at LGS I'm going to try it for both 50BMG and 375CT
Vithavouri N570, gun details as posted above, 38” Bartlein mate, load is 124.5 with a TPL of 4.310 inches. Just watch the BC, hornady gives it as 0.497 but its trued at 0.466 at 2500m, 5/5 impacts.
We have 3 cheytacs shooting A-tips into a quarter inch at 100 and none of the chambers are the same. Each chamber is roughly 0.070 different in freebore.
We have an additional 3 guns all shooting a PTG reamer and they like 4.240 with the A-tips and 142 grains of H50BMG.
We have several snipetacs and they like 3-5 grains more powder than the standard 375 cheytac.
Picture is 3 shots at 100 yards 0.120 group 4 Mils high of point of aim.
We have an additional 3 guns all shooting a PTG reamer and they like 4.240 with the A-tips and 142 grains of H50BMG.
We have several snipetacs and they like 3-5 grains more powder than the standard 375 cheytac.
Picture is 3 shots at 100 yards 0.120 group 4 Mils high of point of aim.
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To summarize its tough to give a actual seating depth number with the 375 cheytac due to the huge variation in freebores from the various reamer manufacturers.
They seem to like a large amount of jump with a very slow powder and you don't need to shoot Retumbo to get best accuracy as 5 of our last 6 match winners used H50BMG at 2147 yards.
Edit: if you use the CCI primers it's only a matter of time before you experience hangfires.
They seem to like a large amount of jump with a very slow powder and you don't need to shoot Retumbo to get best accuracy as 5 of our last 6 match winners used H50BMG at 2147 yards.
Edit: if you use the CCI primers it's only a matter of time before you experience hangfires.
My friend and I have been testinghis BulletSeeker..It picks up the 1st shot and thats it.I had it on a 33XC and a 300 PRC.. Same results.Toget it to pick up a shot I had to turn it off and back on each time.On a 416 Strokerit only picks up 1st shot as well.We had tried it on 4 duifferent phones.Same results.My LabRadar pickedup allbut one shot..
I shoot a 375 Chetac and was shooting 427gr MTAC until I shot thru AB radar for a PDM.Its good tp 2K yards and then not so good.I changed to 40o0gr Lazers and 425gr Lazers.We will howit shakes out.I thought the BulletSeeker would be a greatr tool after watchingMark& Sam After Work on YouTube. It worked great.So whats the real problem? Any Ideas? This bad one has cost the 5 or 6 sales from guys at my local rifle range.
Wher have you been shootinh matches at CamelJockey230; ? Have you been to any ELR matches lately?
If you're having "truing" problems past a mile, consider these variables:
- laser rangefinder errors, usually ranging the terrain behind your target, a very common source of error - "dispersion" of the laser beam, which changes with distance, and varies with the terrain past the target
- velocity variability, minimized with shot-to-shot measurement w labradar or magnetospeed
- BC changes with velocity, or differences from published values, minimized by Applied Ballistic "custom" curves
- BC variation of the bullets, from bullet to bullet, or lot to lot
- scope truing, which really comes in past a mile - have you checked your "clicks"? It is VERY hard to get right, requires special equipment and 2 hours time at least to get it right, I have several threads on this - you need an 8 foot or more "tall target", range to the target measured with a Leica Disto D2 or similar, or a LONG tape measure, NOT your +/- 1 meter target rangefinder which is completely inadequate for the task
- Zero errors, addressed in the Hornady 50 podcast - is your "zero" based on 3 shots? If so, it's probably off by a click or more
- Cant of the rifle, either in set-up, or changing without you noticing during a shooting session (rifle recoils rightward usually)
- changes in atmospheric conditions between shots in a session
- Coriolis, which kicks in significantly past a mile
- powder temperature variation, intrinsic, or introduced by ambient temperature or chamber temperature, especially with long chamber "dwell times" and barrel heating up during a shooting session
- Humidity of powder
- is your "slope" or angle to target changing on the longer targets? Meaning are you shooting more "up the hill" with the longer shots?
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Jaclyn Bryan. ... Jaclyn did something pretty awesome today. She shot a 72” target at over 2.4 miles away, 4227 yards to be exact.
NorCal and so far 3 wins this year with the 375
Yes, the wind is in a category all its own. I was focusing on elevation. When I got into this ELR stuff in earnest about 10 years ago I gave myself fits trying to figure out why my drops didn't match what the computer said
Congratulations on the wins.
I thought maybe you were at Spearpoint Ranch, KS with us this past weekend.
Hiw far are you shooting in NorCal.?
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The bullet seeker we used was deemed to be faulty, exchanged for a new one, now no problems, has been a bit of hit and miss getting a good one apparently, the fella selling them over here will exchange no worries
Can you guys tell me where you are now with H50BMG? Finally got a pound.
Case, charge, your load, velocity, barrel length, COAL, where your hit pressure.
Case, charge, your load, velocity, barrel length, COAL, where your hit pressure.
Everyone is running a different reamer from what I am seeing. My load works well in my gun but it is hard on brass in other guns. I ran 142.5 at just shy of 3000 fps.
Two other shooters who shoot with us are running 138 and 134 to save brass life.
Two other shooters who shoot with us are running 138 and 134 to save brass life.
I'm on my 6th firing of 375 CT with Peterson grass at 3115 fps abd 400gr Lazers at 144.5 grs of RL50.
Brass still good.Primer Pockerts still tight.
Brass still good.Primer Pockerts still tight.
With Peterson brass, Fed215s, .010 off lands I had hints of pressure at 138 grains of H50BMG. 29” DT factory barrel and 138 grains of H50BNG yielded 2991.
I used your seating depth values (.100”) off lands & 134.5 grains of H50BMG velocity of 2815 average and had almost same hoke groups (until the DT fun started)
I used your seating depth values (.100”) off lands & 134.5 grains of H50BMG velocity of 2815 average and had almost same hoke groups (until the DT fun started)
I'm running 34 in K&P brarrel,215 Primers also.I was using H50BMG but the pressure and spikes in temperature changes led me to change.I live in Southeast TX abd it changes alot and I shoot in KS,SD,GA and VA so it didn't work for me.My shooting partner uses it (H50BMG) though.IT just did not fit my gun.However he now shoots at 416 Stroker but still uses it in his 33xc.
I’m at 139gr RL50 and 400gr CEL’s @ average 2996 - 36” barrel, Peterson brass is going strong 7x fired
I just bought 100 Bertram brass.I can't find Peterson in stock.Ive shit it once.Nothing changed in velocity .I put a few in random order to see if I noticed a change on another day.No difference in leading POI .They were expensive though.Hopefully things improve.
Are you SHOOTING in ELR IN Kansas or SD or TX?
I run 400 grain Cutting Edge Lazers at 3170 fps in Peterson brass without any issues. 36 inch bartlein barrel 8 twist
The guys I shoot with can't go that hot without seeing pressure issues.
Seating depth also varies alot because everyone is running different reamers
The guys I shoot with can't go that hot without seeing pressure issues.
Seating depth also varies alot because everyone is running different reamers
So what should be my upper charge with Bertram 390 A-tip @2.250” and H50BMG?
I have some loaded with 132.5 & 135 gr. Should I go to 137.5? I don’t want to be at or near max. I want room to spare for temperature or powder humidity variability. My Bertram has to last me a long time. Has 6 firings on it already and going strong and I don’t want to ruin my streak of luck
FWIW QL says my charge of 137.5 RL50 is nowhere near max pressure but I’m using 350SMK with weight increased to 390 grains and a slight adjustment to make useable case volume comparable between the two. But at 2960 fps from 34” barrel, it would seem QL is wrong (with my fudged inputs) and that I am near max. IIRC I went to 140 and backed off for better accuracy and SD but I don’t remember. I need to get better at making reloading and range report notes
I have some loaded with 132.5 & 135 gr. Should I go to 137.5? I don’t want to be at or near max. I want room to spare for temperature or powder humidity variability. My Bertram has to last me a long time. Has 6 firings on it already and going strong and I don’t want to ruin my streak of luck
FWIW QL says my charge of 137.5 RL50 is nowhere near max pressure but I’m using 350SMK with weight increased to 390 grains and a slight adjustment to make useable case volume comparable between the two. But at 2960 fps from 34” barrel, it would seem QL is wrong (with my fudged inputs) and that I am near max. IIRC I went to 140 and backed off for better accuracy and SD but I don’t remember. I need to get better at making reloading and range report notes
I am using 133gr AR2218 ( H50BMG) with the Hornady 390gr Atips @ 2900 ish.. I have 19 loadings on my Bertram brass .. Lost 2 with split necks out of the batch of 50..
This load produces ragged hole groups at 200yds and 1/2 or less MOA at 1000yds..
That’s what I needed to hear. 132.5 H50 BMG should be about same pressure as 137.5 RL50. Just 50 fps slower of QL is a reliable guide.
Full report to follow but H50BMG somewhere in the range of 132.5-137.5 is THE powder for the ATIPs in my barrel. Way more accurate and consistent than RL50 and about the same speed. 2910 to 3010 from 34” pipe. I’m gonna take the middle ground at about 134-135 and 2950-2960
First group top left (ignore POI) is 132.5 H50BMG Bertram 4.250" .100" off lands. (One error in the whole sequence: my brass for some reason was slightly oversized, I needed to adjust my sizing die, not sure why, but needed another 0.003" shoulder bump and chambering was slightly hard, probably an issue with brass from two different barrels, problem fixed now.) First one was clean bore, cold bore, cold shooter and it was the outlier, and it was also 50 fps slower than the rest of the group so I excluded it from the stats for velocity. Ignoring that shot, the group is clearly under 0.5" for shots 2-6. 2910 fps, SD 6 fps.
Second group at 135 grains went haywire. First two shots were the top two in the group, almost one hole, 2951 and 2957 fps.. Shots 3&4 went to hell, low & right. Suppressor was slightly loose. Tightened. Then the next two shots didn't register on the magnet and the battery went dead. Replaced it and replaced the magnetospeed closer to the bore line. Next two shots went below the first two but speed was 3000 fps, inxplicably. Last two fell back in line in the lower part of that vertical group (excluding the two outliers) and the last two were right there at 2950-2960. Let's chalk that up to equipment failure.
Third group is the right one with 137.5. Bolt lift was notably slightly harder and there were very faint ejector swipes. Still, 4 of 5 in one hole, and abotu 1/2 MOA.
When I got home, i resized and reprimed first the 137.5 and I know for a fact the primer pockets were looser (but useable). So 137.5 is too hot for long term use of brass. The 135 and 132.5 were still tight (all had 5x firings before this session).
I'm going to settle on 134 grains and test that tomorrow I hope. SHould be pretty close to woofercau 133 load, allowing for seating depth and chamber differences and give me wiggle room. And be right abotu 2950 fps, just like my RL50 load but hopefully with better accuracy, SD, and less temp variation.
Second group at 135 grains went haywire. First two shots were the top two in the group, almost one hole, 2951 and 2957 fps.. Shots 3&4 went to hell, low & right. Suppressor was slightly loose. Tightened. Then the next two shots didn't register on the magnet and the battery went dead. Replaced it and replaced the magnetospeed closer to the bore line. Next two shots went below the first two but speed was 3000 fps, inxplicably. Last two fell back in line in the lower part of that vertical group (excluding the two outliers) and the last two were right there at 2950-2960. Let's chalk that up to equipment failure.
Third group is the right one with 137.5. Bolt lift was notably slightly harder and there were very faint ejector swipes. Still, 4 of 5 in one hole, and abotu 1/2 MOA.
When I got home, i resized and reprimed first the 137.5 and I know for a fact the primer pockets were looser (but useable). So 137.5 is too hot for long term use of brass. The 135 and 132.5 were still tight (all had 5x firings before this session).
I'm going to settle on 134 grains and test that tomorrow I hope. SHould be pretty close to woofercau 133 load, allowing for seating depth and chamber differences and give me wiggle room. And be right abotu 2950 fps, just like my RL50 load but hopefully with better accuracy, SD, and less temp variation.
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I’m still playing with H50BMG but it is CLEARLY magic sauce for the 390 ATIP. 134 makes stupid small groups but I think it’s pushing it w pressure (photo1). Tonight I split hairs and fired 5 132 grain and 6 134 grain loads. 11 total (duh!) in 4 different strings (barrel cooling between) all with same POA and got this 11 shot group measuring 0.644 MOA (photo2). So, I’ve spent hundreds of $$$ to confirm what woofer has been telling us for several pages in this thread - 133 is just about perfect in Bertram brass.
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That load will hold 1/4 moa or better at 1000mtrs...
Proved it many a time..
Proved it many a time..
That’s magic , and more or less where I got to with Peterson brass and rl50 x 400cels, I have had to slow down my “quest” due to brass availability, it’s like finding rocking horse turds - anyone know where any is ?
COAL 4.250 is .100 off in my barrel which is a PAG reamer called “375 CT DT” the same one DT uses
That’s what we’re looking for and you found it! Nice work!
What’s your barrel length and speed?
What’s your barrel length and speed?
