Dasher load development

[Keith Glasscock]

I'm finally ready to shoot my first dasher. I need a little advice.

Here is what I have:
30" Benchmark .237 bore barrel chambered with a ptg no-turn reamer - .104 freebore on a Barnard
Lapua hydro-formed brass .003 neck tension
105 Berger VLD - naked
Varget
CCI-450 primers

I have a pressure ladder loaded up from 31.5 to 33.3 at .010 back from a hard jam (still touching).

I'm also planning on shooting some groups while out for the first time, what load band should I use as the top of the load testing? I'm already set up to try 32.5 and 32.8

Should I go higher? Lower? Is my pressure ladder high enough to likely catch the top?

Thanks,
Keith

 

[ProneKing]

For a naked bullet Dadher into the lands you may be well into the pressure signs by 33.3. Just be careful.

 

[dkhunt14]

With that freebore you are probably close. I don't know about Benchmark barrels as to what most people shoot. With a Kreiger you would be close to the ones I shot. I use 155 freebore and BR4 primers and Broughton barrels and I can shoot 34 grains. I had one Kreiger you could only shoot 32 grains. I had a Hart and you are close to what I could shoot in it. Depends on Barrel and I don't know how much the primer would change the pressure. I shoot the 105 about 10 in. You maybe should start lower and work up. You don't have to load a lot of rounds. Load one or 2 to foul the barrel and load one starting at 31. Better to start low. If you only load one of each you won't have so many to pull if you hit max.

 

[DJ111]

I would shoot all of your cases with a light load first to finish forming them before you start looking for pressure or groups.

I am not sure how close your cases are to be fully formed and the right head space?

You may see false pressure if your short on head space.

Good luck with the new gun!

 

[Keith Glasscock]

My plan is to shoot the pressure ladder first, then shoot groups with the loads I have that are within reasonable pressures. I'm more trying to figure out what to take and minimize the number of rounds I have to disassemble afterwards.

If you have velocity data for loads that are into the lands, I'd appreciate it. I have QL, but no basis for predictions.

Fwiw, my last benchmark made little pressure and amazing velocities in 30 cal.
That doesn't mean anything for this barrel though.

 

[Tim Singleton]

I would shoot all of your cases with a light load first to finish forming them before you start looking for pressure or groups.

I am not sure how close your cases are to be fully formed and the right head space?

You may see false pressure if your short on head space.

Good luck with the new gun!

Great advise here.
The first firing is not an accurate indicator.
you really can't get an accurate pressure test until second firing

 

[Alex Wheeler]

I also hydro form my cases. You will see pressure a little sooner on the first firing. I agree with the other post, you dont need to push it to the max on the first firing. I had a barrel that like 34 grains of rl 15, so you will want to load higher than you think you should, just stop when you see pressure.

You didn't mention the bullet your shooting, but hybrids seem to like .010 off touch in the 3 barrels ive had. And powder nodes have been between 32.5- 34 grains of rl 15 or varget. I dont think most barrels will take over 33.3-33.5.

 

[Bkluke]

I would shoot all of your cases with a light load first to finish forming them before you start looking for pressure or groups.

I am not sure how close your cases are to be fully formed and the right head space?

You may see false pressure if your short on head space.

Good luck with the new gun!

I'm with Dallas. 8)

 

[pawpaw77]

I have two dashers. One has a bartlein, one a kreiger. Both like 32.5 grains of varget, cci 450's, 108 bergers, jumped .020. I experiment a lot with bullets and powders and always end up going back to varget. Both guns shoot tighter groups with 32.5 grs. But I only shoot out to 400 yards.

 

[Keith Glasscock]

Thanks for the help guys.

Went to the range today and shot loads from 31.4 through 33.3 looking for pressure. Didn't find it...

At 32.2 - 32.5, I had velocities in the 2920 range and groupings in the 1's (just barely 1's, but 1's) and 2's.

At 33 grains I had 2970 and a group in the 2's.

I only shot 3 at 33.2 with a nearly vertical string ~.4

At 33.3, I had 3000 fps - still no pressure. Head expansion measures .0002" or less

I now have 33 rounds through the tube and another 195 to fully fireform. I think I'll stick with the 32.2 - 32.5 load until they are all formed. By that time, the barrel should have sped up so I can give it a final tune.

 

[Tim Singleton]

Mine also like 32.5 gr Varget at 2940
That mid 2900 seems to be a good node for a lot of people
Looking good