Posted: 8/1/2007 7:55:57 AM EDT
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Currently I am learning handloading under a UK CIP [UK SAAMI equivilant] instructor and want to experiment with shooting out to 1000 yards but to do that I need to hot load and my instructor has no experience loading for the AR15. The cartridges once loaded are a little long for the mags so I need to load singly but in a prone position. What is a safe procedure for doing so? The reason I ask is I am concerned about 'out of battery' problems. Both myself and my instructor would like to know what baulking mechanisms are built into the AR15 to prevent the firing pin striking the primer before the bolt locking lugs are fully engaged in the locking lug recesses. many thanks tb ps: straight pull speedmaster in .223, leupold optics. Experimenting with Vitavouri N133/N540, fed match primers, sierra 68/80gn matchking/Lapua Scenar bullets [new lighter ones] and Lapua brass. |
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Stick the round in the chamber and trip the bolt release. That's how it's done. If you remove the unfired round thereafter, you will see a small firing pin dent on the primer. It's perfectly normal. But you must ensure that your primers are properly seated. The AR can not fire out of battery. Until the lugs rotate and the carrier is cammed into it's firing position, the hammer can not strike the firing pin. 80 Sierra's will get you to 1000, but not as well as a VLD. You'll have to push them over pressure. It can't be done within limits. I don't think N133 is a good choice, a little too slow. When the Army were shooting their V8 load, they used N135. Others use Reloder15, (Varget is too slow) N140 & N540. Go and search some Highpower sites. There's people out there who've been doing what you are for years and there's a wealth of knowledge around. When I used my AR to come second in the 1000yd match at the PR Nationals, I used 80 JLK's over 26.5gn N540 with a Rem 7 1/2 primer and Winchester brass. They were jammed .020" into the lands and clocked out at 2955fps  Brass was a one shot deal though  Sierra's work best at about .010" off the lands. If you're using Lapua brass, make sure it's the stuff that says MATCH on the head. The older stuff creates too much pressure and not enough velocity. Mark ETA: I wasn't the first to score well at 1000yds with the AR, Mousegunner Dave finished second in the same match a couple of years before me with an almost record score. Your UK CIP loading instructor (whatever that is) probably won't like the methods for loading the AR "hot". These are: Load until you get hard extractiion. Load until you blow a primer clean out of the case. If either of these regular occurrences happens.......back it off half a grain and have at it.
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Fantastic, that info helped me a lot, thanks for the response. The 'CIP Approval' my instructer has is: Commission Internationale Permanente (CIP), an international association of proof houses (UK/EU equivalent to the US SAAMI) Its just he has never worked with AR15's.. tb |