MINI PROJECT RIFLE
REMINGTON 700 SPS TACTICAL by Laurie Holland
solid contact and would therefore likely stay that way as the former flexed under firing pressures and maybe wouldn’t see its position and the tension placed on it shift around inconsistently under varying chamber pressures. Well, hopefully not too much, as barrels twist around far more than you might imagine. So we decided to leave things be until we’d had two or three range sessions with a variety of bullet weights and types – it’ll be interesting to see too what rectification – i.e free-floating the barrel - does to group sizes and impact points.
The other issue was the length of chamber throat freebore. This is the first re-barrelling job I’ve had for some time where I’d no idea how much freebore I’d have, other recent work involving supplying the gunsmith with an inert round using the desired bullet seated to my required COAL. I suspected Peter’s people would chamber it short as Armalon puts these barrels on its much modified Remington 700 ‘PR Rifle’ that uses an AR15 / M16 magazine in its 223 Rem version. This limits COALs to 2.255-2.265 inches depending on the make of magazine - my alloy Colt AR15 examples requiring the shorter length, some synthetic models allowing a bit more. Conversely, the A.I. mag on my rifle is based on the 308W/260R etc. box and allows COALs of nearly 2.7 inches, so that 80gn bullets - even 90s - can be seated without excessive intrusion into the case-body.
No matter, the barrel as received works out nicely at this stage as I intend to use the rifle to undertake a full 223 Rem handloading development programme starting with 40-55gn bullets in expanding, FMJ and match types working up to 82gn match models. (The 1-200mm twist rate won’t stabilise the very long 90s.) Many mid or heavyweight 0.224 bullets are designed for deep seating at AR15 magazine operation COALs too, most 68-75gn match models as well as the 77s from Berger, Lapua, and Sierra.
When I finally get around to loading much longer 75-82gn long-range models that I’d want to seat well out in the case, I’ll have the throat reamed out to a suitable length - a cheap gunsmithing job that doesn’t
need barrel removal. Unlike many box magazines, the A.I. type has no difficulty in coping with reduced length cartridges – it feeds SAAMI COAL or even shorter examples smoothly with 100% reliability.
‘Diggle Sunshine’ So, it’s a simple matter of loading up 100 cartridges using four very different weight match bullets and seeing how they shoot. Brass was no problem as I had lots of little used Winchester and Lapua match cases on hand from my former 223 Rem (now 6.8mm Rem SPC calibre) SSR-15. Having been used in a straight-pull rifle and what that means in terms of high pressure loads equating to hard extraction, they’d had an easy life.
Full-length resizing 100 used Lapua examples turned them into a good match with the Armalon chamber providing easy chambering and, equally important, no-effort extraction after firing. Tough Remington 7½BR primers were installed in still tight pockets.
After some thought, 52gn and 75gn Hornady A-Max projectiles were selected, having given good results in other 223 Rem rifles, although the 700 SPS Tactical’s OEM 1-9 heavy barrel hadn’t cared for either model. The evergreen 69gn Sierra MK was a natural choice and, wanting to try as heavy a bullet as the throat would accept, it was a choice of three makes of 77-grainer, the Lapua Scenar being the winner.
To keep things simple, speed up the loading process, and avoid barrel cleaning between batches, I wanted to use a single powder. This is asking a lot from a single powder grade with a 52 to 77gn bullet weight spread, but Hodgdon’s data for H4895 gave full pressures and impressive MVs for this range, albeit with a compressed 26.5gn maximum charge weight under the 52.
My SSR-15 had also seen its smallest 77gn bullet groups with this powder, although you can’t guarantee such results transferring to other rifles and barrels of course. Another benefit of sticking to one powder was that I now have an RCBS 1500 Charge Master electronic powder dispenser - a super device that saw me weigh out 100 charges much, much quicker than I could have done with a measure and scales but which needs a little time and effort to change powders.
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