.223 Bolt Rifle Barrel and Bullet Compatibility

aviumvenator

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I have a new .223 barrel on a bolt gun that I am working up loads for. I found an acceptable load combination with AR Comp and 77 SMK. I tried the 75 ELDM and can not get anything close to acceptable results. I also tried 2000 MR with similar poor results. I plan to run another test with the ELDM when I get some H4895. I did let the barrel cool between strings and tests were shot at 100 yards.

Question
Am I at the point where I need to accept that this barrel will not shoot the 75 ELDM or are there other variables I could change that might significantly improve performance with this bullet?

Barrel = PBB CF, 1:7.5, 17.5”, 300 rounds.
Load = AR Comp, S&B SRP, Hrn 75 ELDM

The first picture (grid = .1 mil) shows the results of a small test to confirm the variability I obtained from the 75 ELDM. Prior to this I tested a range of charge weights and seating depths with similar results.

D211ACF6-2FBE-4CD0-9F0C-45A495E5BB63.jpeg


The second picture is the load I settled on for 77 SMK and is included to show the potential of the system. The 1.844 is the seating depth.
B86D33C8-B705-4854-BE2A-1662BFD76595.jpeg
 

skyrep

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Feb 20, 2018
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I have a Savage Model 12 26" barrel and have great success with AR-Comp. I load my 75 ELD-Match to 2.390 (coal) which is .064 off the lands. Velocity: 2887 w/ SD's: 9.8 and 1/4" at 100 yards.
 

Doom

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You really haven't given us much to go on. What CBTO/COAL are you using? The 77 gr bullets are standard tangent ogive and are not particular about seating depth. The ELDM is a different beast. Depending on your chamber you may have trouble with it.
 
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aviumvenator

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I have a Savage Model 12 26" barrel and have great success with AR-Comp. I load my 75 ELD-Match to 2.390 (coal) which is .064 off the lands. Velocity: 2887 w/ SD's: 9.8 and 1/4" at 100
That seems pretty good. I have tried .01, .04, and .06 off but no joy. What twist are you running?
 

aviumvenator

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You really haven't given us much to go on. What CBTO/COAL are you using? The 77 gr bullets are standard tangent ogive and are not particular about seating depth. The ELDM is a different beast. Depending on your chamber you may have trouble with it.
I tried 10, 40, and 60 off. 10 off was the worst. 2.353, 2.381, 2.411 were the OALs.
 

MarkyMark007

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not-on-google.shit
Yes I have CCI 450 and Wolf SRP. I didn’t try those because I don’t want to believe that a primer would make that much difference but I will run a test with one or both of those to try.
primer will make a difference. but this does not mean that s&b primers are bad. because they are the best, but maybe with your setup are not optimal and can be others better suited.
 

SilencedShooter11B

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I had several barrels that did not like Hornady 68gr BTHP, handloaded with two powders (Varget and RE15) to all kinds of lengths and the usual suspects of variations, nor would it shoot Black Hills factory loading of them either. 69gr SMK, 77gr SMK, and even 75gr Hornady shot fine which I thought strange because I was under the impression it was similar in profile to the 68 except for a longer bearing surface
 

aviumvenator

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I tested rounds with 450’s in place of the S&B’s. That change did not improve the 75 ELDM’s. I also tested 77 TMK’s and those along with the SMK’s are where it’s at with this barrel. When I find some H4895 I will revisit the 75’s but I also plan to order another barrel with the longer throat from PVA.
 

MarkyMark007

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not-on-google.shit
I tested rounds with 450’s in place of the S&B’s. That change did not improve the 75 ELDM’s. I also tested 77 TMK’s and those along with the SMK’s are where it’s at with this barrel. When I find some H4895 I will revisit the 75’s but I also plan to order another barrel with the longer throat from PVA.
can you tell how different were speeds and ES/SD values ?