Figured I’d post some info I gathered today. Just in case anyone comes across this thread and wants more info on the 260.
Measured my brand new/unfired hawk hill 260 ATX barrel. Ironically it is identical to my 260 criterion match barrel on my savage. OAL of the rounds are within .002” when touching the lands from both barrels. This is with 142 SMK bullets
I looked at my notes. From my 26” criterion barrel I settled on the groups that were best on the lower end of my testing. To save the brass and barrel a bit. Those loads are running 2835 average and shot 1/2 moa at 300 and 600 for 5 shot groups. Bullets are .010” off the lands
My second node was at 2875 fps. Again .010” off the lands. Which shot just as well as the 2835 fps loads. My speed crept up to 2890 fps with the same loads just testing from touching to .020” off the lands.
I tested loads on fire formed brass up to 2930 fps on the 142 smk. That’s as high as my book shows and I don’t know if I ran into pressure signs there or not. That was many years ago and just can’t recall. I didn’t make a note of pressure in my book though.
This is with
Lapua Brass
H4350
CCI BR2
142 SMK
The criterion and hawk hill are both sammi spec chambers for reference
Now for something interesting and something that is mentioned above and should be taken into consideration when selecting between the 6.5 or 260. The OAL and magazine length. Below are rounds for my criterion barrel but for reference both the criterion and hawk hill would have these rounds seated .010” off the lands.
The pics are best I could get with Magpul pmag (AICS), AICS metal mag and AIAW mag. You’ll notice the Magpul has slightly less room than the metal magazine both in AICS. Easily measured with a caliper as well but the pic shows just how close these bullets run to the limits
The AW magazine however has a considerable amount of space left to seat the bullet out. Well past my needs with these 142 smk bullets.
Just thought I’d share some measurements, magazine concerns and real world speeds here for those still considering a 260.