6 Dasher Conundrum

[Sjett]

Shooting 1k prone match week before last . (Prone Iron sights) I shoot in Sharpshooter class so my scores are normally in the 181 to 189 with typical x count of 6 to 8. Shooting my normal 1k load 33.2 R15, lapua Brass, CCI 450s, Berger Hybrids seat -.020. Have .120 Throat. First two 20rd matches were normal with 186-2 and 181-3 (missed wind change and kept shooting 8s on left. anyways to my question. Didnt have enough lapua brass(couldnt find other box of brass). So i use my 600 yd brass which is Remington brass with 3 firings on them, normal load for this brass is 32.8 R15, 7.5s and Hybrids or Nosler RDF bullets. But i loaded the 33.2 of R15 and 7.5 primers. it shot the best score i have shot at 1k with irons of a 194-6 x . So it had mild bolt lift and ejector swipe and primers look ok . so what would i do to duplice this load in the lapua brass so i dont get pressure signs like the Rem brass. Did i just jump up to high node for that brass. All ammo loaded on autotrickler.

 

[mgunderson]

Start with checking the speed of both loads. 50-100fps and I would expect a node change.

 

[Sjett]

The Range i was at was using the shotmarker targets and it showed my avg speed at target as 1695 for first 20, 1697fps on 2nd 20 and last one with rem brass as 1699 fps avg. dont know how accurate that reading at target is on shotmarker. Using lab radar my Vel. for lapua brass is 3095 with sd of 6, for 1k load. Temp change was less than 10deg differance for that day of shooting. It was low 80s

 

[DT]

Also try testing the 71/2 primers with the Lapua brass.

 

[ChrisNZ]

.. dont know how accurate that reading at target is on shotmarker. ..

I wouldn't be relying on it if you need the absolute numbers. The SMT system velocities often doesn't relate well to the real numbers. Might have some use as relative measure.

 

[dmoran]

@Sjett
Copy the primer, neck tension, and all brass prep steps from the Rem-case load to the Lapua-case.
Could check the capacity variation between the two, compute the load densities, and then match the load density if need be also.
Good luck

 

[Sjett]

Thank, will gather all data and post , have a two day 1k match Saturday and Sunday will be shooting 120 rds, may shoot scope one day just to test

 

[ShootDots]

I would try RL-16. It will produce L-O-A-D-S of velocity and friends of mine use it in Dashers and it also produces excellent accuracy! You may find it gives you better velocity and at least as good of accuracy as RL-15.

 

[Sjett]

OK, Remington case capacity avg 40.35 gr h20 H-40.8 L-40.12 This is out of 10 cases
Lapua Brass Avg 40.975 gr h20 H-41.1 L-40.78
All cases on third firings and all preped the same. .266 bushing , .012 neck, trimmed 1.5260
lapua brass turned 100% at .012
Remington 95% at .012

 

[Sjett]

How would I figure the load density Dmoran do I need any more info than what I have gathered

 

[Lefty Trigger]

In my BRX the Rem 7 1/2 primers give about 40-60 fps for any given load. If your close to max with a different primer the Rem's will push you over.

 

[swd]

I would try RL-16. It will produce L-O-A-D-S of velocity and friends of mine use it in Dashers and it also produces excellent accuracy! You may find it gives you better velocity and at least as good of accuracy as RL-15.

I'll second this^^^ And it has excellent temperature stability. It works so well in the Dasher and BRX I don't even bother with RL15 or Varget in those cases any more.

 

[Sjett]

I still haven't had a chance to check the vel. On,the remington load , but did shoot 3 matches last week end 20 rd each at 1k going up .2gr and as loads went up , groups at 1k got more round and x count went up using lapua brass. Right now I'm at 33.8 primers cratering due to remington big firing pin , but still round edges and easy bolt open. As my honey do list gets checked off will have more time for shooting outside of a match.

 

[Sjett]

Dorman
Reading a lot of your post about throat length, do u advise me going to a longer throat than the .120 I'm using now. I have a .2435 throating reamer. So I can run it out further as needed.
Thanks