Down one node - Dasher

[Keith Glasscock]

I've been shooting my 30" dasher for a couple of years. With a .104 free bore and 105VLDH, I've been running 33.1 - 33.4 grains of RE-15 and a short (.005) jump. It groups really well for F-class with velocities in the 3050 range. At 6 firings, the brass is done due to loosening primer pockets. The new brass I fire formed recently will not take that level of pressure though. The 45 cases (on their second firing -first one was fire forming with Varget) I shot yesterday are all showing excessive head expansion and significantly increased primer pocket sizes.

I did check the rest of my firformed brass and they have tight pockets, so the damage was done yesterday.

So, my question is: Where is the next node down? I was guessing that I should see it around 3000 - 3010 fps (32.4 - 32.7 grains of RE-15)

For those of you with experience, what did you find?

 

[Keith Glasscock]

Forgot, barrel has 1700 rounds on it - throat has moved out a little.

 

[Alex Wheeler]

You really should not have an issue there. Are you sure you dont have a carbon issue? Also a true .104 is pretty short. .135-.155 works well with the 105s.

 

[pressedRat]

i've had a dasher for about 4 months. fire forming has been a bit of a learning lesson. .269 neck. i turned the brass down to false shoulder, loaded 30.5 grains varget and it shot great. first batch i turned the necks a 2nd time after adjusting the neck turning to go a bit further down the neck than the first turn.. i then left my turner at that depth and the next set of cases i didnt do a 2nd turning because my false shoulder was a bit longer. my first loads on my first set of brass showed 32.7 varget and 33.1 rl15 shot well.

so im shooting at a target and my primers start to blow. the the ones that didnt blow the base was blown out like you described. i can barely or not quite get the base of some of my cases into my primer seater. i thought i had bad powder. so i go back and check some of my brass, re-turn the 2nd group and they shoot ok, no blown primers. but i ended up with a lot of brass screwed up.

what was happening was (im pretty sure) is that the necks were over-tight at the base of the neck, pinching the brass tight around the bullet and causing serious over pressure. some cases showed no signs, some showed blown out bases that would not fit in the primer tool and some simply were ruined with blown out primers. my rounds after the first firing were .010 off the lands.

bottom line, at least for me the brass needs to be checked after the first fire-forming and in my case, every neck needs to be turned a 2nd time to get that lowest part of the new neck after the shoulder has been blown out.

as an aside, at 30.5 grains varget with 105 hybrids in my fire formed dasher brass im getting .25 five shot groups at 200m and consistent sub .5 ten shot groups at 300m. basically a 6br load shoots lights out in my rifle. at least at 2 and 300 meters. The longest range i can shoot at locally is 600 yards so i may see how that mild load does at 600. it obviously puts less stress on the cases and i get a few more loads out of a pound of powder.

live and learn..

 

[Jet]

Keith

I push the 105 Hybrids around 2970 and get pretty good results. Primer pockets stay tight.

Good Shooting

Rich

 

[Keith Glasscock]

You really should not have an issue there. Are you sure you dont have a carbon issue? Also a true .104 is pretty short. .135-.155 works well with the 105s.

The funny part is that I did have some cases in the original batch that made 10 firings and are not falling-out loose. Instead, the seating force is too low for my taste.

Yes, indeed, it is a .104 freebore. I have the reamer here. My next barrel was chambered with a .150 ish freebore. After doing some load development, I've decided that I will not do any more short freebore Dashers (at least not for 105's)

I borescoped the barrel after cleaning it before this shooting session. No carbon ring, and it was JB'd to bare steel. Also, I shot 22 rounds of 33.3 grains in older brass before shooting 33.2 with new brass. The older brass didn't show any pressure problems. I'm wondering if the case heads just aren't as hard in the new cases.

 

[Keith Glasscock]

Keith

I push the 105 Hybrids around 2970 and get pretty good results. Primer pockets stay tight.

Good Shooting

Rich

What barrel length are you running?

 

[johara1]

What is your loaded round diameter and what is your neck diameter? i run around 34 gr. of RL-15 and a 105 or 106 bullet with no trouble. Did you check for carbon at the end of the chamber? and the bore? the cases i'm using for testing been loaded over a hundred time and never lost one for a loose primer . If the primers are loose it start right up front when i prime for fire forming i mark them and they stay loose. you may have some fat bullets. i run a .135 free bore……. jim

 

[Jet]

All are either 29" or 30" and 7.75 or 8 twist

 

[Kebee]

All are either 29" or 30" and 7.75 or 8 twist

I destroyed lots of brass shooting 33.2 RE 15. I was getting 3080 fps with 33.1 RE. It was too hot for my rifle. I think the next node down will be 32 to 32.4.

 

[Keith Glasscock]

Thanks to everyone that has responded so far.

Jim - No carbon problem. Borescope shows good. Loaded neck .268. - Chamber .2705. Same bullets I was running before - .2435 at the pressure ring. Velocity has not increased. I'm getting 3070 with 33.3 at 65 degrees F. If I come down to 33.1, the velocity drops below 3050 and the groups open up.

Jet, Thank you!

Kebee,

I'm going to search the 31.9 - 32.7 area and see if I can find it. My best guess is that it should fall around 32.4 at 65 degrees.

All,
I did forget to note that my first batch of brass was hydroformed and this new one was fireformed. The first batch was also shot through one full rotation at 32.4 Varget (pretty mild) while the barrel was speeding up before it was introduced to RE-15 at full pressure. I wonder if the hydroforming and/or mild loading might have hardened the case heads some. If not, this new batch of brass is just a touch softer than the older batch.

 

[CaptainMal]

FYI I get 105 Hybrids to shoot around 33.2-.4 gr. Target and also 32.2-.9 gr. That puts them either 3,020fps or 2985 fps. Always get way over 10 loadings per case at either grain weight.

MUST keep carbon out so Bore Tech carbon remover is essential with Varget.

 

[Jet]

I destroyed lots of brass shooting 33.2 RE 15. I was getting 3080 fps with 33.1 RE. It was too hot for my rifle. I think the next node down will be 32 to 32.4.

Like Jim, I have run up to 34gr of 15 with no pressure signs. Chambers start out with a 135FB.

Rich

 

[johara1]

Keith, that seems like a very high velocity for 33.3 of RL-15, i'm 3030 at 34.0……. i had shot 33.9 to 34.1 all last year. jim

 

[savagedasher]

I have brass that I shot 20 times using
H 4350 with 105 jumped .020 and the pockets at still tight. 3060 fps . Larry

 

[Keith Glasscock]

I have brass that I shot 20 times using
H 4350 with 105 jumped .020 and the pockets at still tight. 3060 fps . Larry

I intend to try that with the next barrel - it has more freebore. From my testing, I can reliably get a little over 36 grains of H4350 in the case and not be compressed. It takes me far longer to load due to the slow pour and ridiculously long drop tube.

What velocity do you get with a 28" barrel (my next barrel)?

 

[savagedasher]

I intend to try that with the next barrel - it has more freebore. From my testing, I can reliably get a little over 36 grains of H4350 in the case and not be compressed. It takes me far longer to load due to the slow pour and ridiculously long drop tube.

What velocity do you get with a 28" barrel (my next barrel)?

3050 with 28'' 3070 with 30'' depending on twist. Larry

 

[Loggins J]

I form mine with 29 grains of varget and shoot mine at 32.4 RL 15 at 2980 I havent had any problems

 

[Keith Glasscock]

Apparently, I need to learn how to use my borescope. There was a carbon and copper problem, just not in the throat. It took a lot of JB scrubbing to get out. I'm thinking that my old load deserves another try.

BTW, I figured it out when I went to shoot a couple of rounds with 32.0 of RE-15 and got pressure signs. The magnetospeed reported 3050 fps. That got me to looking further down the barrel.

Chalk one up to learning.

 

[DCRYDER]

i've had a dasher for about 4 months. fire forming has been a bit of a learning lesson. .269 neck. i turned the brass down to false shoulder, loaded 30.5 grains varget and it shot great. first batch i turned the necks a 2nd time after adjusting the neck turning to go a bit further down the neck than the first turn.. i then left my turner at that depth and the next set of cases i didnt do a 2nd turning because my false shoulder was a bit longer. my first loads on my first set of brass showed 32.7 varget and 33.1 rl15 shot well.

so im shooting at a target and my primers start to blow. the the ones that didnt blow the base was blown out like you described. i can barely or not quite get the base of some of my cases into my primer seater. i thought i had bad powder. so i go back and check some of my brass, re-turn the 2nd group and they shoot ok, no blown primers. but i ended up with a lot of brass screwed up.

what was happening was (im pretty sure) is that the necks were over-tight at the base of the neck, pinching the brass tight around the bullet and causing serious over pressure. some cases showed no signs, some showed blown out bases that would not fit in the primer tool and some simply were ruined with blown out primers. my rounds after the first firing were .010 off the lands.

bottom line, at least for me the brass need.

i've had a dasher for about 4 months. fire forming has been a bit of a learning lesson. .269 neck. i turned the brass down to false shoulder, loaded 30.5 grains varget and it shot great. first batch i turned the necks a 2nd time after adjusting the neck turning to go a bit further down the neck than the first turn.. i then left my turner at that depth and the next set of cases i didnt do a 2nd turning because my false shoulder was a bit longer. my first loads on my first set of brass showed 32.7 varget and 33.1 rl15 shot well.

so im shooting at a target and my primers start to blow. the the ones that didnt blow the base was blown out like you described. i can barely or not quite get the base of some of my cases into my primer seater. i thought i had bad powder. so i go back and check some of my brass, re-turn the 2nd group and they shoot ok, no blown primers. but i ended up with a lot of brass screwed up.

what was happening was (im pretty sure) is that the necks were over-tight at the base of the neck, pinching the brass tight around the bullet and causing serious over pressure. some cases showed no signs, some showed blown out bases that would not fit in the primer tool and some simply were ruined with blown out primers. my rounds after the first firing were .010 off the lands.

bottom line, at least for me the brass needs to be checked after the first fire-forming and in my case, every neck needs to be turned a 2nd time to get that lowest part of the new neck after the shoulder has been blown out.

as an aside, at 30.5 grains varget with 105 hybrids in my fire formed dasher brass im getting .25 five shot groups at 200m and consistent sub .5 ten shot groups at 300m. basically a 6br load shoots lights out in my rifle. at least at 2 and 300 meters. The longest range i can shoot at locally is 600 yards so i may see how that mild load does at 600. it obviously puts less stress on the cases and i get a few more loads out of a pound of powder.

live and learn..

If your neck is .269" it's gonna be hard to create a false shoulder unless you necked it up first. Most loaded blue box brass measures around .268" and the old gold box .269".