Chamber too short?

[1S2K]

New guy here. Thanks for allowing me to join you shooters on this forum. I've been lurking here for awhile and realized I needed to join.
I'm not new to shooting, but am returning to reloading after a 30 year lay-off. Yep, I'm old I guess.
Anyway, I got a new Rem700 XCR LRT in .223 Rem and am in the process of breaking it in by shooting some factory ammo in it before beginning to work up a hand load.
My problem: Firing Fed GMM in 69gr and 77gr SMK's, some of these factory rounds chamber with no problem while some of them make it very difficult to lock the bolt down. All rounds fired ok, with no signs of high pressure. The bolt face was washed in brass a bit but from the camming action of closing the bolt I think.
Some of the factory stuff measured COAL of 2.440 to 2.257 in both 69 and 77 grain bullets. The shorter ones gave normal resistance. What's going on here? Chamber too short? Cartridge length too long? Bullets will require being seated deeper for this rifle?
Even the longer COAL's are less than max in Sierra manual. Never faced this before and have shot lots of rifles and ammo. If you can help, I will deeply appreciate it. Sorry for being so long-winded on my first post.

 

[KMart]

Have you checked to see if there are any rifling marks on the ogive of the bullet when the bold cams in hard? If you are getting the marks, you could have a short throat on your chamber.

 

[rocketron]

check the rim of the case. i got a 700 sps that had a hard closing bolt. the extractor would take a nice chunk off the rim.

 

[1S2K]

Thanks guys for the replies. There are no rifleing marks on the bullet except for a faint ring running halfway or better around the bullet just forward of the case mouth. There is no damage done to the rim by the extractor. This is a mystery to me! I have found a very slight notch formed on the lip of the case mouth on the rounds that were hard to chamber.
My far from expert opinion is 1. The factory ammo does not have bullets seated to a consistent depth ; 2. My chamber has a bit of a short throat (is this good or bad?) and 3. I will have to seat bullets a bit deeper in handloads to compensate for this
If it were your new rifle, what would you do? Send it back to Remington? Have your gunsmith check it out and maybe lengthen the throat if necessary? Other? Thanks for your help. Very frustrating.

 

[LIUNA]

Have you checked the shoulder and length from shoulder to head, if you haven't bumped the shoulder back it will cause this problem.

 

[rocketron]

the notch in the lip maybe your problem if it was not there before you chambered the round. next time you shoot it try hand feeding the rounds into the chamber. this should help figure out where the notch is coming from.

 

[243winxb]

a faint ring running halfway or better around the bullet just forward of the case mouth. I have found a very slight notch formed on the lip of the case mouth on the rounds that were hard to chamber.

Possible chamber problem, but first take measurements of the factory rounds causing the problem. Measure maximum trim length & neck diameter. Compare to SAAMI maximums for the cartridge here. http://www.saami.org/PubResources/CC_Drawings/Rifle/223%20Remington.pdf

 

[bigedp51]

If you look at the SAAMI drawing below you will see that allowable .223 chamber headspace can be from 1.4636 min to 1.4736 max.

The manufacturing tolerances for the cartridge case can be from 1.4666 to 1.6585

On a chamber at minimum headspace or GO a newly manufactured cartridge case headspace can be .003 "LONGER" than the chamber.

You could have a tight chamber or new cases with overly long cartridge headspace or both.

 

[1S2K]

Guys, I think you may have nailed the problem. From what I can determine, my chamber is a bit on the tight side and I know for a fact that some of the factory cases are on the long side of max. I'm carrying it to gunsmith next week to look for a possible burr in the throat also that may be causing the small nick on lip of case mouth.
So, does this mean accuracy may not be affected if I trim closer to minimum case length and seat bullets out a bit farther? Do you think I have a major issue here or a problem that can be solved without having the chamber reamed? Man, I appreciate the help from all.

 

[Webster]

Not sure what you mean by a notch on the rim of the neck. If the case mouth has a shiny spot after extracting the case must be rubbing somewhere. Measure the case length and compare it to spec.

 

[newgun]

How is she shooting? If it shoots good and you are going to load for it you should be o.k.. But if you want to run the only the longer bullets you might have a bit of a problem Let us know what your smith tells you please.

 

[hogan]

Very doubtful your chamber is "too short".

Too short for heavy weight VLD bullets is more likely. Dunno about your rem 700. Newer .223 tacticals might have a fast twist barrel, but pretty sure that almost every other Rem 700 chambered in .223 is setup for 55gr or maybe 62gr bullets and NOT the long match weights.

If anything, factory 700 chambers are always on the longish side. If you consider a Go Gauge spec to be a minimum oal chamber dimension, the typical 700 rifle will be about .005" longer. This is a brass measurement function that you can verify using an RCBS Precision Mic or best a Wilson Chamber Gauge.

Probably need to throat your chamber for the longer VLD or longer ogive heavy bullets. You are confusing bullet jam with chamber dimension, I think....

What I would verify before spending money or time on that factory barrel is the Twist Rate. Most likely you have a 1:12 or 1:14 Twist rate and neither is going to work very well, if at all, with bullets much over 55gr. Bet if you try chambering some 55gr or lighter factory loads you'll see no problem closing your bolt...

Really want a 1:7 or 1:8 twist to shoot the heavier match bullets and a reamer pattern designed specifically for these bullet contours and dimensions.

 

[1S2K]

Thank you guys for the help. After following advice given, I concluded I had a headspace problem. Took the rifle to my excellent gs (who makes custom firearms) and he verified this rifle came from the factory with too short headspace. Go-gauge was a no go. So now it's off to Remington for them to correct their problem. How common is this problem?

 

[hogan]

If not too late, might ask your gunsmith to hold the rifle.

A short-oal chamber is THE BEST Solution to making a factory rifle (or any other) shoot well.

There are couple of solutions. Sending the rifle back will get you the standard cavernous chamber that won't shoot worth a damn.

A thicker recoil lug will move your barrel a thousandth or two out thus alleviating your problem.

Try mic-ing your brass with an RCBS Precision Mic or Wilson Case Gauge. Some virgin brass will be way under SAAMI or Go-Gauge spec and thus should chamber easily. Just mic your brass and use what chambers.

Your gunsmith can part-off .-02 or .035" from base of your sizing die, or face-off 10 or 20 thousandths from top of your shellholder. This should easily allow you to size your brass to your chamber.

Can also have your gunsmith touch up your chamber with a reamer in his shop, or uniform the bolt face. Might actually be the boltface that is out of spec...

Probably gonna take months to get your rifle back from Remington, if they do anything about the problem.
The problem you think you have isn't a real concern.

Hope you can still get your rifle back and look at all your options more closely....


Good luck!

 

[K22]

check the rim of the case. i got a 700 sps that had a hard closing bolt. the extractor would take a nice chunk off the rim.

I have the same problem with a Remington 700 varmint in 223. The extractor is resisting the case seating into the face of the bolt. Mine is going to the gunsmith this week - hopefully there is a cost effective remedy since this rifle shoots under 1/2 moa.

PS: the end side of the rim (as viewed from the primer facing me) on some of my cases show significant erosion from the erector riding over it. It doesn't occur all the time but frequently enough to be a real nuisence.

 

[1S2K]

Thanks for that advice Hogan. Was in there this afternoon and rifle not shipped yet. He said Remington is averaging about 4-6 weeks to get work out.
I thought they ought to pay for their screw up. That's why I told him to send it back. He told me he could ream the chamber some but that would/ might require some lug work too and it wasn't all that cheap. I'll try to call early tomorrow am and try to discuss further with him the possibilities if he didn't ship it already.