Alpha 6.5 Creedmoor Brass users what loads are you using with 140 ELD-M's

[dreever]

Had to significantly drop my loads due to less case capacity. Curious as to what others are using. Measuring case head expansion between new brass and after first firing just above the extractor groove is giving me .00178 which still seems like a bit much.
What are you thoughts? That's with using only 38.0 gr of H4350.

Danny

 

[dreever]

Just tried 37.0 gr of H4350 the case head expansion was .00149 which can be considered acceptable.

Perplexed to say the least.

 

[rockywlw]

I have been using 40.6 gr. of H4350 with a velocity of 2655 avg. This with 140 ELDs and 142 Sierra HPBTs. I have never measured the case at that point but I'm not getting any sign of being to hot.

 

[D2junky]

I’m running north of 40 grains with 4350 or rl17 with no sign of pressure in a Tikka factory chamber. I’m gonna say a tight custom chamber will likely generate more pressure. I have not clocked the loads.

 

[mustang-cars]

I 'm almost finished running through my 400 pieces of virgin LRP Alpha brass. I have a very slow lot of H4350 powder right now so I have to pour on the coals to get the velocity I was getting with Prime brass. That being said I'm using 42.7gr of H4350 to get 2845fps average out of a 26" Bartlein on a RPR. I do have them seated out pretty long due to the fact I have 2000 rounds on the barrel. I do every once in awhile get a slight bit of bolt lift(heavier) on a round here and there at those velocities but its barely noticeable. With those wounds there's a slight extractor mark(almost cant see it) but no ejector mark or primer cratering. For comparison my old lot of H4350 was giving me 2850fps in Prime brass with 42.3gr and this new lot with prime I had to run up to 43.2gr to get the same velocity. The prime brass was the same lot of Prime if been using. I haven't lost any velocity in this barrel yet so its not that. Checked it with some rounds from the old lot as a control.
SAAMI spec chamber.

 

[canezach]

I was running 40.0 grains of RL16 with the 140 ELDMs. MV in the 2840s in a 26" Benchmark DTA barrel with a Silencer Tech suppressor

 

[spife7980]

With those wounds there's a slight extractor mark(almost cant see it) but no ejector mark or primer cratering.

Extractor mark?

 

[mustang-cars]

Extractor mark?

Little shiny spot where I assume the extractor would be. I assume that because its not an ejector mark that I know for sure. I guess the proper term would be extractor swipe I believe. Not really sure if that’s what it is because it’s so faint but I do know it’s the beginning of over pressure because you get a little additional bolt lift from those rounds.

 

[spife7980]

Gonna have to question that again. The extractor grabs the case on the front side of the rim to pull it out of the chamber. The ejector is what pushes the case out away from the bolt face. It sounds like you’re describing an ejector except for you say that you aren’t. Pics? I can’t believe that it would be going into the ever so slight relief on the outer edge and not the ejector.

 

[mustang-cars]

See the shiny rectangular spot by the “A” in Alpha. No signs of a round ejector mark to my eye.

 

[mustang-cars]

Gonna have to question that again. The extractor grabs the case on the front side of the rim to pull it out of the chamber. The ejector is what pushes the case out away from the bolt face. It sounds like you’re describing an ejector except for you say that you aren’t. Pics? I can’t believe that it would be going into the ever so slight relief on the outer edge and not the ejector.

I get that the extractor pulls from the complete opposite side of the rim from where that mark is in the picture. Maybe it’s just the ejector rubbing a bright spot on the brass when it’s hot and I’m rotating the bolt to unlock and eject a case?

 

[spife7980]

 

[dreever]

Just tried 37.0 gr of H4350 the case head expansion was .00149 which can be considered acceptable.

Perplexed to say the least.

Factory Hornady 140 ELDM load is 41.7 grains of some unavailable powder to us seated 2.810.
I measured a new round at the case head and got .46665 after firing it measured .47050. That's .00395 case head expansion! No wonder Creedmoor brass doesn't last. I've always used case head expansion as a pressure guide. Never going with more than .0015 on the first firing. It's worked well in all my rifles .223/.308/.6BR. So having said that a load of 37.7 grains of H4350 in my Creedmoor with virgin Alpha brass is even beyond my acceptable level. It's .00168.
I'm still perplexed with the Creedmoor.