For the public consumption regarding AR loads....or what we find works.

We dont have the benfit of thousands of pounds of gas to start the extraction, so load for accuracy (unless you are going long range) or you may well find that you wont be getting the bolt open if the case decides not to spring back. GGG brass works well as it is quite hard. Because we cycle rapidly they get hot but need to feed well, so most of us FL resize and use the cases 2-5+ times. I will often use a batch for matches 5 times then drop them to practice for a few loads, but the CSR scene is awash with 5.56 GGG once fired at circa £50 per thousand (or an H83 box full). Penny a load...peanuts.

I load mag length and crimp. I shoot CSR so expect circa 1MOA prone mag rested, this is good out to 600, you may want more but with a 4x scope from some very dodgy positions, 1MOA at 100y is better than the 36mm at 30m acceptance required on the L85

You will find that with most loads, putting a 77 grain bullet into the case at mag OAL will compress the load. I have not seen any pressure issues to date with 77SMK/24.6Gr RS52 or 75PPU HPBT 24.7Gr RS52 and I am well on my way to barrel no 3.

I literally copied the meplat to head dims of an RG SS109 round and took that as a datum. The RG bullet is quite pointed so it does make the same load with HPBTs look a bit duimpy but they feed well without catching bullets on the feed ramp and splines. Many mistake damage caused by ejecting a live round as damage caused by loading. The bullet can get dragged between 2 splined and get gouged on the way out, as cn the case necks.

As regards sizing, I screwed up a new die setting which cause me to get case head seps in a comp. I got away with it but scrapped the lot on firing. I then took fired round and litterally kissed it with the die until it fed well and checked it in a Dillon head space gauge where it registered as bolt action (longer than semi auto). It has been fine ever since.

I now keep a broken case extractor in the butt...on the grounds that a bit like baldricks bullet, if I own one, I wont need it

Why RS52 and not Varget, IMR4894, N140? Well N140 works, but RS52 gives progressive pressure (rather than the spike of N140) and good velocities. The other 2 are difficult to find and make you grow 2 heads.

STM and nice clean brass also aids movement in the mags and loading. Mine will (and should) fully chamber under its own steam, even when hot.

Also, I find the spring, bold carrier bearing surfaces, gas horn, bolt rings, cam pin and the rear of the locking splines respond well to a bit of molly grease (the black airgun stuff).

Love your ARs, they will keep going.

I shot my BAR10 for the first time on Sunday. Being braked it showered the firers either side with bloody bark chips but it dont half go well. One for CSR society only though I think