88 TMK Loading Thread

[Jmedin]

Tikka T3X 1:8 twist 223 AI 88 TMK 18" bbl suppressed
3800 ft elev. 50 degrees

According to my MagnetoSpeed Chrono, 88 ELDMs are @ 2800 fps MV with
same case/powder/primer combo. 0.015 jump
I haven't trued this yet but I'm pretty optimistic
it will replace the 77 TMK as my top hunting bullet of choice ( which I've been
extremely happy with.)
Will do some ten shot groups to get a real zero.

First ten bullets out of the gun.
Adjusted scope after first group
X grains in top and X+0.5 grains in lower
1" dot

What’s your load?

 

[mt terry d]

Lake City brass, CCI 450, LeverEvolution

 

[SeanM243]

Two more small hogs down to the 88 TMK, both DRT. Impact velocity on both these would be around 2600 fps. I was unfortunately in a crunch so I didn't clean either one.

 

[Thegman]

Two more small hogs down to the 88 TMK, both DRT. Impact velocity on both these would be around 2600 fps. I was unfortunately in a crunch so I didn't clean either one. View attachment 1050047

Did you get exits on both shots? If so, what size do they tend to be?

 

[B_Reynolds_AK]

So my load of 25.0 of N150 with the 88’s that was working fine, is now popping primers. Backed off to 24.5 and the last 6 rounds I fired this evening popped out as well.

FWIW, I’ve never popped a primer in my 223, even when working up higher than that to find pressure, until I messed with the NAS3 cases and had those primers all either puncture or come out last week. Related? There is a slight ridge a few mm down from the tip of my firing pin from firing those NAS cases.

1x fired ADI brass. I have Starline 5.56 brass on back order and also Lever powder on hand to try.

 

[Thegman]

So my load of 25.0 of N150 with the 88’s that was working fine, is now popping primers. Backed off to 24.5 and the last 6 rounds I fired this evening popped out as well.

FWIW, I’ve never popped a primer in my 223, even when working up higher than that to find pressure, until I messed with the NAS3 cases and had those primers all either puncture or come out last week. Related? There is a slight ridge a few mm down from the tip of my firing pin from firing those NAS cases.

1x fired ADI brass. I have Starline 5.56 brass on back order and also Lever powder on hand to try.

Are you using the same firing pin as the one exposed to popped primers with the NAS3 cases? Check to see if/how much deformation on its tip. Sounds like there's some.

I know with ARs, firing pins can be ruined by popped primers pretty easily, but really easy to replace in that case.

Another spot to check is the firing pin hole in your bolt face. Look to see if that has been catered/eroded by gasses. Another thing that happens with ARs at times.

 

[SeanM243]

Did you get exits on both shots? If so, what size do they tend to be?

Yes, both exited on those. The one on the left, the exit side is pictured. The one on the right, entrance side is pictured, exit size was about dime size with no bones hit as my shot was a little back.

 

[Castle Rock]

So my load of 25.0 of N150 with the 88’s that was working fine, is now popping primers. Backed off to 24.5 and the last 6 rounds I fired this evening popped out as well.

FWIW, I’ve never popped a primer in my 223, even when working up higher than that to find pressure, until I messed with the NAS3 cases and had those primers all either puncture or come out last week. Related? There is a slight ridge a few mm down from the tip of my firing pin from firing those NAS cases.

1x fired ADI brass. I have Starline 5.56 brass on back order and also Lever powder on hand to try.

Probably time to get it borescoped, my money is on a problem in the neck area, either a carbon buildup or long cases pinching the neck.
If that’s not it maybe your die adjustment is out and cases are being sized too short.
I don’t think it’s the firing pin.