Round 2 testing primers in the 22 BRA

[JamesnTN]

Round 2 of testing the 22 BRA using 4 different primers and approximately 20* warmer temps.

The 450m didn’t show what it did earlier. The 205m was looking really good until the last shot dropped low left. I’ll retest the 205m just to make sure but the BR4 and S&B really shows promise with shapes of the groups. I need to tighten up neck tension and I believe one of those 2 will come in like I need. Also I believe I’m at the upper end of the powder charge of 34.0 of H4350 so I need to back off and test 33.8 and 34.0 again and see with the warmer temps.

 

[boltfluter]

James,

Always enjoy your testing posts. Looks like you are just about there. Can you explain your logic of using moly, as I believe we are the last two on the planet running it? Hope you are doing well James.

Paul

 

[JamesnTN]

James,

Always enjoy your testing posts. Looks like you are just about there. Can you explain your logic of using moly, as I believe we are the last two on the planet running it? Hope you are doing well James.

Paul

Paul,

For my thinking it’ll help preserve Barrel life especially at the throat area. With these little bores and aggressive powders anything I can help reduce friction has to help.

 

[TAJ45]

OK... moly... I had this thought early on when moly was more in vogue: From my reading, it takes more powder to achieve the same velocity vs nekkid. More powder is counter intuitive to throat erosion - no? I'm not aware of a moly coated bore being less susceptible to heat.

Just spitballing here from reading many a thread.

 

[JamesnTN]

By adding more powder to achieve same velocity doesn’t necessarily mean it’ll creat more wear. Hence less friction to achieve same velocity by adding more powder. Once the throat area and barrel has a coating laid down and proper cleaning then it will by lab tests slow the wear down in the throat area.

 

[TAJ45]

Interesting, I thought the #1 deleterious item was amount of heat?
I guess we're in the realm of dancing Angel's and pinheads. Friction = heat and less friction = less heat but then where does the intersection point of less friction cross the increased heat track?
It would seem, taking your lab statement at face value, that there would be a movement toward moly, not away. Just pondering....just pondering.

 

[Nick_Mansfield]

Correct me if I’m wrong, but typically you use slower burn rate powder on coated bullets to help throat erosion, using rl17 35grs instead of rl15 33grs, 4350 instead of varget, 4895,8208
Pretty close to same velocities. And I maybe on the warning track in right field with my head in the sand..I use tungsten coated on one of my barrels..