6 x 47 Lapua
105 Match Target Hybrids
3,000 FPS
ES~5 to 7 FPS
H4350, 38 grains (IIRC, will double check in the AM)
CBTO (will check in the AM). Never measured COAL, don't care. I'll give you some COAL numbers to go with CBTO.
Update;
Went downstairs and measured/looked.
(Load for Bolt Action, Mag fed, AICS Mags. Bighorn TL-2 and Ultimatum Deadline builds, both chambers identical dimensionally)
2.951" CBTO
SAC Comparator, 1.000" OAL (including insert)
SAC 6mm insert, 0.241" ID (Sinclair ~ 0.237", see below)
2.640", 2.636", 2.636" COAL (Sample of 3 rounds)
Just touching lands
38gr H4350
Both builds shoot in the 1's and 2's fairly regularly
I never look at COAL (other than the initial specifying of reamer). I always go off of CBTO. However, you need to be careful with CBTO measurements. I used Sinclair comparators for probably 20 years. I decided to upgrade to SAC (Short action Customs) a couple of years ago and have been quite happy with them. The only reason I went from Sinclair to SAC was better fit/finish on the SAC's.
There wasn't anything wrong with the Sinclairs. They are made of aluminum and I saw the SAC's and that they were made of stainless, so I decided to "upgrade". At that point, I had two sets of comparators. On a lark, I decided to measure the bores of both the SAC and the Sinclair. To my great surprise, the Sinclair was (IIRC) 0.237" or so. I then measured the bore of the SAC insert and it measured 0.241".
All those years of using the Sinclair, it didn't occur to me that the bore would be anything other than 0.243". That assumption on my part was true for both the Sinclar and the SAC. As I thought about it, it began to make sense. The reason that manufacturers "underbore" their comparators/inserts is that if they made the bore exactly the same size as the bullet, there would be a great deal of CBTO measurement variation due to just exactly where the bullet "got thick enough to stop further travel of the comparator insert". A ten thousandth of an inch in diameter/bore variation at close to full bullet diameter will translate into a lot of CBTO measurement variation.
I mention this because of my experience, I treat the CBTO measurement as a relative measurement, not an absolute measurement. The only thing that I care about is that from reloaded round to reloaded round, the measured CBTO value is always the same. In that regard, I don't care what the number "is", I just want it to always be the same.
