Primer showdown: WOLF vs. CCI #41

[markm]

Shot another test load with the Demon CCI 41s. 23.7 gr of IMR 4064 pushing 69 gr RMRs. 7 rounds out of a 20 inch barrel, I got 2836 FPS with a nice SD of 8. The problem is there was 1.5" of vertical stringing.

Everything about the load was livable except the vertical stringing.

[opngrnd]

Shot another test load with the Demon CCI 41s. 23.7 gr of IMR 4064 pushing 69 gr RMRs. 7 rounds out of a 20 inch barrel, I got 2836 FPS with a nice SD of 8. The problem is there was 1.5" of vertical stringing.

Everything about the load was livable except the vertical stringing.

Maybe a slight reduction will get you in the node?

[markm]

Maybe a slight reduction will get you in the node?

Could be. It's surely worth a try. No harm in spinning up another 10 at 23.4 gr or so.

[MarshallDodge]

Shot another test load with the Demon CCI 41s. 23.7 gr of IMR 4064 pushing 69 gr RMRs. 7 rounds out of a 20 inch barrel, I got 2836 FPS with a nice SD of 8. The problem is there was 1.5" of vertical stringing.

Everything about the load was livable except the vertical stringing.

That's probably the bullet.

[Coal Dragger]

Edit: Oops. Thread drift. Feel free to move or delete. Sorry....

So, assuming primer detonates, how many thou short of a 556 go guage (don't have numbers in front of me from checking my hs guage against one) might you start seeing case failure with factory loads?

Edit: go guage 1.4636. my rcbs thimble measures it at -1/2. Sized cases are -3 to -5. Fired cases from 3 different chambered guns average measure +1, +3, +4+. All guns set back factory rounds to -4 to -5 upon chambering and remeasuring. Have seen no signs of head separation except on 2 lots of ppu brass fired 2 and 3 times. No cracks, but last sizing left a hard ridge on outside of case in front of web. Have other lots of ppu fired 3 and 4 times with no signs.

Sorry, just wondering how far from the failure zone I may be.....

5.56mm NATO headspace has an acceptable range from 1.4646” to 1.4706” measured from the .330” diameter datum line of the shoulder in the chamber. So you have .006” to play with from minimum to maximum.

[triggerjerk]

Thanks, Coal Dragger.

[markm]

That's probably the bullet.

Could be, but instead of the usual 1.5ish scatter, these were mostly vertical with like 1/2" of horizontal.

[MarshallDodge]

Here is the reason that I offer the bullet as the issue. Some groups from yesterday's 100 yard session-

The real reason was to test some 64 Gold Dot blems with N133. Four 5-shot groups were shot and they all looked similar to this, sub MOA


Then the 69 3GH. My neighbor shot another five and his group looked similar


After that I shot some random 62 BTHP and 77 SMK to recover the brass

[Coal Dragger]

If your groups at 100 yards are that tight but display vertical stringing don’t rule out the variable causing that as you. Minor differences shot to shot in the butt stock position or position of the friend on the rest can easily cause a bit of vertical stringing.

In case you wanted your own group measurements:

[MarshallDodge]

If your groups at 100 yards are that tight but display vertical stringing don’t rule out the variable causing that as you. Minor differences shot to shot in the butt stock position or position of the friend on the rest can easily cause a bit of vertical stringing.
....

Thanks for the measurement. While I do struggle with vertical stringing, that group was shot with some random 62 and 77 grain ammo left over from several reloading/sessions.

The 69 3GH just doesn't like this barrel, but isn't much better in my other gun either.