Tikka CTR .260 case/chamber spec help needed

[Darkop]

I am trying to chase an accuracy Gremlin and need some case prep help.
Rifle:
TIKKA CTR 260
KRG Bravo chassis
NF ATACR
NF rings
All of the screws and bolts have been double checked for tightness and torqued to proper spec with inch # torque wrench.

Load:
45.1gr IMR 4350
Fed 210
Berger 130 VLDT
NK tension .002

This load has occasionally produced .5 to .75 MOA groups but I seem to get unanswered fliers that I can't figure out. I was checking case specs today and saw that SAAMI overall case length is 2.035" with trim length at 2.025" My virgin Lapua brass is 2.200" to 2.206" Prime os 2.01" and Remington is 2.02" Could I be looking at a minimum SAAMI spec chamber in my rifle and (ALL) of this brass is too long? Would this possibly cause the "fliers" I'm seeing? It seems like a lot of trimming to do on Virgin Lapua brass not to mention the length of the factory Prime and Remington ammo.

What do you trim your .260 brass too? Thoughts? I'm open to suggestions!

Thanks in advance,
Darkop

 

[the_accuser]

I would reach out to Lapua, seems your brass is too long. I just measured a number of virgin Lapua .260 brass I have and each are 2.022 - 2.024". I trim all my 260 cases to roughly 2.025".

 

[dino67]

Try a Berger 140gr Hyb or 135gr Classic Hunter. Less sensitive to seating depth. I had a tikka in 7-08 that was a 2 moa gun with 168gr VLD's at best. Diff powders; seating depths etc. Went back to 168gr classic hunters after 12mths of nil supply. 3 consecutive 5 shot groups at 200m, .7", .6', .7". Still have a box and a half of VLD's gathering dust. Worth a try.

 

[USPcompact]

Did you mean the Lapua brass length is 2.020-2.026” instead of 2.200-2.206"? If the length is actually the latter then that’s way too long, and you’d almost certainly be experiencing excessive pressure. Check the shoulder length of new brass versus the shoulder length of fired brass and then do the same for those empty cases checking OAL.

I shoot a .260 CTR quite often. My trim length for Lapua brass is 2.030 using a WFT. The length of the Lapua brass when new was 2.020-2.023”. I haven’t measured the chamber length yet but may do so if I get a chance in the next few days. That said, I don’t think that is what’s causing your issue.

My 20” .260 CTR likes the 130 Hybrid, 140 Hybrid, and 143 ELD-X. The ELD-X gives me more velocity, the Hybrids slightly better precision. I’ve tried the Berger VLDs and due to the throat geometry in the barrel they did not perform nearly as well as the more jump tolerant bullets like the Hybrids and ELDs. The ELD-X is jumping ~60 thousandths, the 140 Hybrid about 50 thousandths, and the 130 Hybrid is jumping ~40 thousandths. With H4350 and 210M primers it has been no problem getting SDs into the single digits.

 

[Darkop]

Correct the virgin brass overall length is 2.200" to 2.206" Looks like I have some long necks on this brass.I am able to load to .008 off the lands with the 130 VLDT's. I guess I better do a BUNCH of trimming and get this brass to 2.025" and run some tests.

 

[FLIGHT762]

How can you even chamber the 2.200" brass? In all of my 308's, brass over 2.048"( .033" over max) won't chamber and in my 223 Wilde chambers, brass over 1.785" (.025" over max) won't chamber.

Are you sure you have your numbers right on the Lapua brass? If so, I would trim the brass to 2.025".