[Mercmar]

Could be that this has been discussed in other threads, but I just don't remember seeing it. We all know that 5.56 chambers aren't the same as .223 chambers, and that .223 Wylde chambers are a little different from the other two mentioned.

Prior to my recent build of my varmint AR with the RRA Wylde-chambered barrel, I'd only loaded for my Bushmaster, which has a 5.56 barrel. I'd always loaded my rounds out to around 2.260", as that's about as long as I can load them so that they'll fit in my mags.

Yesterday, while doing some more test-firing of the new varmint AR, I manually ejected a round, when I was changing types of ammunition. I noticed some pretty harsh rifling marks on the ejected round's bullet. When I got home, I got out my Stoney Point o.a.l. tool with the dummy case and did a little "checking". The fmjbt bullets that I'd used were touching the rifling at 2.225", which is WAY shorter than any other .223 or 5.56 chamber for which I've loaded. Unless I just happen to have acquired a barrel that was short-chambered, then, I suppose, the theory of the very short leade is that one has a lot of flexibility for loading rounds that will fit in a magazine, but will just be a few thousandths off the rifling.

I also checked some Berger 53gr. and V-Max 50 gr. bullets and found that they actually could be loaded a little longer than the aforementioned fmjs, but still not nearly as long as I'd previously loaded them.

I'm about to set up my 650 with my seating die so that I can reseat a bunch of previously-loaded rounds short enough to fit the new AR's chamber safely.

I'm going to e-mail Steve, at Adco, from whom I acquired the RRA barrel, and make sure that I don't have a short-chambered barrel and that the shorter leade is, in fact, intentional.

 

[Wild Rice]

That is normal. The Wylde chamber has a short lead (or throat) so the bullet does not have to jump a gap before hitting the barrel's rifling. To quote the RRA website:

"The .223 Wylde chamber was designed as a match chambering for semi-automatic rifles. It will accomodate both .223 Rem and 5.56mm NATO ammunition. It is relieved in the case body to aid in extraction and features a shorter throat for improved accuracy."

P.S. I would recommend that shooters only chamber live rounds at the range using all safety guidelines. Please don't load live ammo at home to test your chamber.

 

[Mercmar]

I appreciate that info, W.R. I had "sort of" come to that conclusion after speaking with an AR owner/reloading buddy of mine. The advantage of the short throat, of course, is that we have much more latitude in loading rounds that will easily fit into an AR magazine, but that will only be a few thousandths off the lands.

I didn't see anything in my post that would indicate that I'd cycled a loaded round at home, but I agree, particularly with ARs, that's probably not a good idea. I frequently charge my pistols at home, with the muzzle always pointed in a safe direction.

Just got back from the range, having seated several bullet varieties deeper. Groups are doing better. I'm loading 2200, which isn't a particularly accurate powder, and I probably need to bump my loads up a little hotter. Have a pound of H335 and will probably load a few rounds with that next time I'm loading for the AR.

I just noticed that I used the term, "short chambered" in my original post. I know that the barrel's not short-chambered. I should have said "short-throated" or "excessively short-throated."

 

[Wild Rice]

I didn't see anything in my post that would indicate that I'd cycled a loaded round at home, but I agree, particularly with ARs, that's probably not a good idea. I frequently charge my pistols at home, with the muzzle always pointed in a safe direction.

That was not directed at you, as you said you were at the range at the time when you noticed the rifling markings on the bullet. That was meant for any forum readers who might want to duplicate your findings by chambering (and ejecting) a live round. I have a collection of guns, so I try to keep it safe and simple by not chambering live ammo at home.