Need a sanity check: 223 Rem 'match' neck clearance

[memilanuk]

I'll preface this by saying "yes, I'm aware that things like 'match chambers' or 'no-turn necks' are tenuous terms at best." Good?

Anywho... I'm curious what you consider sufficient clearance for a 223 Rem with a 'match' or 'no-turn' chamber, throated for heavy (80+ gn) bullets?

0.250" loaded round in an ISSF chamber (0.2527" neck on the reamer print)? 0.249?

Fired brass is coming out measuring 0.2515-0.252", and while a 0.224- pin gauge will fit down the mouth and through the neck, a bullet measuring 0.2242" @ the pressure ring will *not*.

I hesitate to call it a 'problem', because it seems to shoot pretty dang well at 600yd, but it seems a bit... un-natural.

 

[kyotekiller25]

I thought most guys like to see 3 or 4 thou total clearance these days?

In my R700 223 Wylde I have like 6 thou. Loaded Lapua is .250" and fired comes out at .256"

Not sure exactly what reamer he used as he didn't provide me with a print, but it seems a little odd because the chamber is tight/min spec. I had to bring it back to him because virgin Lapua brass wouldn't chamber without camming the bolt and scuffing the case heads.

 

[NZ_Fclass]

My 250 loaded 223's come out at 253.Works for me.

 

[Woollybugger]

I'll preface this by saying "yes, I'm aware that things like 'match chambers' or 'no-turn necks' are tenuous terms at best." Good?

Anywho... I'm curious what you consider sufficient clearance for a 223 Rem with a 'match' or 'no-turn' chamber, throated for heavy (80+ gn) bullets?

0.250" loaded round in an ISSF chamber (0.2527" neck on the reamer print)? 0.249?

Fired brass is coming out measuring 0.2515-0.252", and while a 0.224- pin gauge will fit down the mouth and through the neck, a bullet measuring 0.2242" @ the pressure ring will *not*.

I hesitate to call it a 'problem', because it seems to shoot pretty dang well at 600yd, but it seems a bit... un-natural.

My .250 neck 22 dasher reamer was considered “light turn” by Dave Kiff when I ordered it. If you need to seat into the donut I would turn them.

 

[memilanuk]

My 250 loaded 223's come out at 253.Works for me.

From what size chamber ?

My .250 neck 22 dasher reamer was considered “light turn” by Dave Kiff when I ordered it. If you need to seat into the donut I would turn them.

Berger 85.5s seated about 13 thou off the lands have about 0.140“ bearing surface in the neck, which is approx. 0.200" long. So *in theory* the bearing surface / boat tail junction should be 60 thou north of the case shoulder / neck junction.

 

[memilanuk]

I thought most guys like to see 3 or 4 thou total clearance these days?

That was kind of where I'm coming from - I'm used to more like 8-10 clearance in my 'match' 308 FTR.

In my R700 223 Wylde I have like 6 thou. Loaded Lapua is .250" and fired comes out at .256"

Not sure exactly what reamer he used as he didn't provide me with a print, but it seems a little odd because the chamber is tight/min spec. I had to bring it back to him because virgin Lapua brass wouldn't chamber without camming the bolt and scuffing the case heads.

That sounds more like a headspace issue than a neck issue?

 

[kyotekiller25]

That was kind of where I'm coming from - I'm used to more like 8-10 clearance in my 'match' 308 FTR.



That sounds more like a headspace issue than a neck issue?

Well if you have 8-10 clearance in a 308 Match FTR rifle, I don't feel so bad about having 6 thou in my 223. I'd like to be in the 3-4 area but it still shoots just fine, so not going to worry about it. My 6 creed also has 6 thou clearance, and my 7-300 Win Mag has 4 thou.

I wasn't super educated when I had these rifles built. Didn't ask for reamer prints or any of that. Just told them what cartridge I wanted and that's what I got... Was before I became a member here. I've learned more here about precision shooting and various measurements and chambers etc than I did anywhere else online in the last 20 years. Still not the best at it, but it's getting little easier.

I don't know what kind of issue it was, all I know is virgin lapua brass was a super tight fit, so I took it back and had him go in another 2 or 3 thou in the chamber so it would close easily and not mess up the case head. That seemed to fix the issue.

I made a thread about it and most guys here came to the conclusion that he was about 3-4 thou under min spec from the information and measurements I gave. Good thing he only lives 30 minutes away. He fixed it, but was kinda grumpy about it at the same time. Well it's not my fault you cut the chamber that short! I didn't ask for that. If you can't chamber a piece of virgin brass without camming the bolt, that's a problem.

 

[NZ_Fclass]

From what size chamber ?



Berger 85.5s seated about 13 thou off the lands have about 0.140“ bearing surface in the neck, which is approx. 0.200" long. So *in theory* the bearing surface / boat tail junction should be 60 thou north of the case shoulder / neck junction.

Typo - should read out OF 253 = so 3/000 clearance.

 

[memilanuk]

Typo - should read out OF 253 = so 3/000 clearance.

So loaded rounds are 0.250“, chamber is 0.253"... what's the fired brass measure coming out of the gun? Can you fit a bullet down the neck of a fired case?

 

[NZ_Fclass]

So loaded rounds are 0.250“, chamber is 0.253"... what's the fired brass measure coming out of the gun? Can you fit a bullet down the neck of a fired case?

Yes - close slip fit. I use Lake City brass, annealed every time.

 

[charlie b]

...If you can't chamber a piece of virgin brass without camming the bolt, that's a problem.

Imagine my surprise when I got a new Howa barreled action in 6.5CM that wouldn't chamber virgin brass at all. Ran it through a Hornady and Lee FL size dies and still wouldn't chamber. Finally took some meat off the bottom of the die until the brass just fit. After that no more issues.

If it wasn't to be a donor action I'd probably have sent it back.

 

[natdscott]

My opinion is that you are too tight. If you were a shooter taking clearances to that level, with a rifle as such, and ammo as such, then (A) you would likely not be here asking, (B) it wouldn't be a .223, and (C) it wouldn't bother you.

Best keep that ISSF squeaky clean at the carbon ring.

.255-256 necks are pretty common, in match AR rifles. Paired with loaded rounds that average .247-.248, it's quite a bit of clearance, but they poop where they eat.

I did have one upper set up at .254, for Lapua, which puts your rounds at about .2495-.250, and that is plenty tight. The upper was only ever to be a single-shot deal with those rounds, and never more than 40-60 rounds between cleaning, so not a problem, but I thought I should put that out there.

I absolutely would do that .254 again, for Lake City, WinFedIngton, etc., but if you were to intentionally set up an AR barrel for Lapua from Mag, then either go .256, or plan to turn a little off.

At any rate, .256 will still group at or under 1/2 Minute, quite easily, so 8+ thou clearance is not really an issue, at the level you are shooting.

That "single shot" .254 upper will half dollar 3/4 of its rounds at 300 yards, though. It's an interesting barrel.

 

[William Vogel]

I shot a lot of bullets from a 223 benchrest rifle with only 0.002 clearance with no problems. I cleaned it every session. I have since rechambered the barrel to 223AI and it now has 0.006 clearance. I don’t think I’ll run another one that tight but it worked.

 

[memilanuk]

.255-256 necks are pretty common, in match AR rifles. Paired with loaded rounds that average .247-.248, it's quite a bit of clearance, but they poop where they eat.

I think that's why the whole thing kind of weirded me out... the vast majority of the .223's I've had in the past have either been factory varmint rifles, or ARs (both Service Rifle and 'space gun' Match Rifle) with Wylde chambers - plenty of clearance, comparatively. Even the 12 FTR & Palma guns I had in 223 Rem (and did pretty well with , back when) had the Wylde chamber.

I shot a lot of bullets from a 223 benchrest rifle with only 0.002 clearance with no problems. I cleaned it every session.

Yeah... I'm probably guilty of letting this thing go longer than I should have previously. I can't quite clean as often as BR guys do, even if I wanted to - just don't have the time/facilities to do that in F-class. End of the day (i.e. 60-100rds) is the best I can manage when I am being OCD (relatively speaking) on the cleaning.

Best keep that ISSF squeaky clean at the carbon ring.

Funny you should mention that... I'd seen one starting to form in this thing and I thought I was losing my mind: a carbon ring in a .223 Rem?!? What the heck! Turned out the nascent carbon ring was relatively easy to get rid of; the hard carbon build-up in the first 3-4 inches of the bore was another matter :/

 

[William Vogel]

I don’t shoot competitively. In a match, I think it would be difficult to watch for the signs and even get out of the race before a problem occurs. I guess practice rounds at home could get you the data for how long an interval between cleaning and clearance problems would exist and know the boundaries. I think the tight neck chamber could have advantages. For me the carbon ring is also easier to remove than the bore carbon.