This is a discussion on Headspace Worries? within the M16 AR15 forums, part of the Rifle Forum category; I got a barrel chambered in .223 Wylde from White Oak Armaments with a bolt that was supposed to be headspaced to the barrel. Now ...
I got a barrel chambered in .223 Wylde from White Oak Armaments with a bolt that was supposed to be headspaced to the barrel. Now I'm worried that the chamber is too short.
I know it's not a gauge for measuring chambers, but using my Hornady headspace gauge the stripped bolt closes with a measurement of 1.4585". Real push needed for 1.4590" and easy with 1.4580".
So I subtract .005" and try to size for 1.4535". I could get there, but only by pushing REALLY hard on the press handle. It dawns on me that the problem is the shell holder hitting the bottom of the die - HARD. RCBS X-Die sizer and Redding shellholder. The shellholder height is right in line with other shellholders from Redding, RCBS & Hornady. (One Lyman shellholder is significantly shorter.)
Wilson Case gauge (why didn't I think of that before?):
1.453" measured on my Hornday headspace gauge is flush with the bottom step of the Wilson case gauge.
1.458" is 0.001" below the top step of the Wilson case gauge
New Hornady .223 REM cartridge measures 1.4545" in the Hornady headspace gauge.
Am I unnecessarily worried or does it sound like the headspace dimension is darned short, even if within .223 REM specs?
I am trying to track down someone locally with a .223 "GO" gauge to check the headspace.
Even if it passes with the "GO" gauge (which should be 1.4636" IRRC), this still seems like an unusually tight chamber, no? Does it mean I have to avoid 5.56 ammo entirely or just check dimensions before buying?
If anyone knows where I can find a 223 REM "GO" gauge in or near Richmond, VA it would help a lot!
You need real gages to use, and the assistance of a qualified smith.
You cannot tell anything in a meaningful (safe) way by using the case gages, especially to the 0.0005" resolution.
Go back to the White Oak Armaments folks and tell them your concerns.
Thanks - your response is polite as can be.
My overall question is simple: Does it sound like there may be a headspace problem?
Sorry for being overly complicated.
I am trying to find a qualified smith with the proper gauges.
I plan to go back to WOA after getting a real headspace measurement and only if there is a problem.
I wasn't worried until I realized that setting up the sizing die according to the standard RCBS instructions would produce overly long cases (in terms of the headspace dimension).
My impression is that WOA is a top notch outfit. I called last week and talked to Jane who told me that they do not keep any records of headspace for specific rifles or bolt/barrel sets but did check it for my bolt & barrel.
I suppose it may have come across a little short... Sorry.
I have dealt with measureing cases (fired and not) and headspace for quite a bit and have found that trying to determine HS by anything but a HS gage is just setting yourdelf up for frustration and misinterpretation of "results".
Th .223 Wylde is a wildcat with no SAAMI specs and uncertain history of development. It's "supposed" to be a "compromise" between SAAMI and NATO chambers, but who do we know who made the reamer and to what specs? I'm not sure what value there may be in the wildcat chambering, there isn't enough difference between .223 Rem and 5,56 NATO to make a difference.
You may also want to check the "leade" of the chamber, to see if it has been shortened which would cause an apparent short headspace.
Unless you know exactly how the chamber was reamed, you may need custom dies. The shoulder may be off, the throat may be off, who knows?
With full humility in this very knowledgeable forum I offer that - again - it seems reasonable but really is iffy to try to estimate actual headspace in an autoloader using fired cases.
When this kind of thing has come up for me I’ve always just taken it to the local LE armorer/gunsmith and paid to have the headspace checked with gages that I assume are stepping up in 0.001 inch increments from below SAAMI/NATO to above the high end to get the actual (NOT estimated) headspace to 0.001 in a clean chamber. I have never had any reason to ever think that I have gotten a bad number as I've never had any failures that I could ever even consider being related to a headspace issue.
If I ever get sets of this kind of gage I will have mine relieved so that I can use them without disassembling the bolt at all.
Frankly, can anyone suggest where to go where all interested posters can buy such a set of gages for at least the 223 Rem/5.56X45 NATO and also the 308 Win/7.62X51 NATO gages in 0.001 increments as sets? I can easily find the go and no go and field sets but the sets stepping up in 0.001 increments are not so easily found. It would be a service in my opinion if anyone could point to where these could be found so that clubs and larger groups could buy and share a set or people with more than the usual amount of need/interest can just buy a set and do it when they feel the need justifies doing it.
Headspace in semi-autos is definitely a matter of interest and being able to get a bona fide valid headspace measurement has real significance for at least safety reasons if not also accuracy reasons. Paired with a headspace gage for a cartridge this should allow a shooter to really make intelligent and deliberate decisions about case sizing and maybe even factory ammo choices and not have any guesswork become a concern.
I sent jbrooks a PM, but everyone should know that I was NOT being sarcastic (for once) when I typed "Thank you - your response is as polite as can be."
Guys, please. I was NOT trying to measure the headspace of the rifle. I simply was trying to set up my sizing die to push the shoulder .005" shorter than the largest case that would fit in the chamber. I had no reason to think that there was a problem until I realized how hard the shellholder was hitting the sizing die when adjusted to get to that -0.005".
The Hornady tool should be called a "shoulder bump gauge" instead of a headspace gauge. Actually, that's exactly what Sinclair calls their equivalent tool.
In .001" steps I've only seen the Forster headspace gauge sets, but they appear to have a reputation for inaccuracy. Clymer headspace gauges seem to be the industry standard. This being the error-net, I don't know whether or not that's true. Someone, somewhere makes headspace gauges in .0005" steps because my SAI Scout came with a tag showing headspace to that accuracy.
The idea of headspace gauges with a cutout for the ejector is brilliant!
At this point, I'm not trying to get an exact number for my AR-15s headspace. I just want to know that it will chamber a "GO" gauge.
JBrooks - I had read all sorts of wonderful things about the Wylde chamber. Headspace between the 223 and the 5.56, with a shorter leade than the 5.56. Sounded perfect. Eh, maybe not. In any event, I have the right tool from Hornady to check the leade and will do so before handloading. Headspace just came first.
Speaking of .223 vs. 5.56, I came across this diagram supposedly from Clymer in my search for headspace gauges this morning:
The base-to-shoulder is different, as is the freebore, and a few others. But no telling what the Wyde chamber is. Perhaps Clymer can send a diagram.
Speaking of measuring cases, I have tested this many times:
Cut off the gas system on the M14 or FAL. I fire 5 rounds, and measure the HS with a custom ring gage of diameter 0.400" (For the 7.62 NATO/.308). ON a CONSISTENT basis, the fired cases are Longer than the chamber HS. By as much as 0.004". Now this was from effectively a Bolt gun. The case expands and the bolt "gives" a tad under 50 KPSI of pressure and so the fired case is actually Longer than the chamber HS.
My spent AR-15 cases average 1.460-1.461" in the headspace dimension. A few were up to 1.462" or a tad more. NONE of the spent cases would chamber after resizing without bumping the shoulder back. They also all stand proud of the Wilson case gauge.
TinMan, sarcrew00's offer sounds like it's be worth pursuing, if just for peace of mind. From the sounds of it, your headspace is probably OK, especially if the bolt closes on factory cartridges freely. It might be on the short side, but, as mentioned, only a set of gauges will tell that for sure.
I'm not sure just why your die set won't bump the shoulder back enough to chamber. I've used X dies with no problem, though I am using a Hornady set for my WOA at present. Just a thought, have you checked the over-all case length? I'm just speculating that maybe the necks might be too long and hanging up at point "F" in the chamber (nice diagram, BTW). Also, IIRC, the X die can do weird things to a case if the length is too long. Have you checked your sized cases against a cartridge drawing (diameters at various points, etc) ? Do you have a standard 223 FL die you can try? Just thinking out loud. Good luck, and let us know what turns up.
liftrat22 - thanks for your thoughts. The case length is fine. The X-Die will bump the shoulder back enough, but only if I set it up so that it hits the shellholder really HARD. There's a lot of resistance to camming over the press arm without a case there at all.
sarcrew00 is going to help me check the headspace this week. A very generous guy!
... if I set it up so that it hits the shellholder really HARD. ...
No ned to do that. You'll risk breaking things. As soon as the die contacts the shell holder leave it be. There will be a little "spring" even in a cast iron O-press, but once the die contacts the SH, that's it.
so many different sizing of the gauges and east over shoeing what is made ....if you get a fn 556 gauge set ..it will scare hell out of you,what is out of spec ! i know my L/W barrel is spot on with 556 and others are off but work well ...you can check the stretch of the fired casing too to the gauge set !