I'm ashamed to state that I believe I need some assistance and guidance reloading some ammo for my 5.56 AR-15 chrome lined barrel.

Background:
I'm married with two young kids.  The kids take much of my time.  Work takes the rest.  I started reloading about 1-1/2 years ago and have read extensively.  I am an engineer and understand how complex this can be, but also how simple.  I suspect that my only AR-15 (chrome lined 5.5.6 chamber) is out of tolerance on the "small side".

Up until now:
I prepped and primered hundreds of cartridges with a used .223 Full Length RCBS die (used).  I also loaded hundreds of rounds with increasing amounts of powder to test at the range.  My first visit to the range (with my new chronograph) revealed that about 10% of my rounds won't even chamber properly.  Another 10% won't eject after firing, due to the fact that they are being forced into the chamber to begin with(?).  I fully resized all cartridges, but failed to check them in the chamber prior to loading powder/bullets.

Now:
I just purchased a Redding small-base sizing die and careful measurements reveal that it is little different from the previous RCBS die that I have used when screwed down +1/4 turn (I purchased, and have the SAAMI specs and dimensions for rifle calibers).

Today:
My bolt on my rifle closes easily when about 1/4 open without ammo. . . yet requires at least 3/4 open to slam home with any ammo except xm193.

Is anyone willing to offer help to me.

Either online or in-person?

Thanks.

M.L.

GO here and take things slow and easy.

You need one of these for each type round you make.

This is also the cheapest way I have found and does not require you to load your weapon as a test.

BRD

BigRedDog,

I already have a cartridge gauge.  My Headspace is fine.  I think that my chamber may be small in  other areas besides headspace dimensions.  I can't afford another upper/barrel at this time to verify my suspicions.

My new small-base redding die still requires that the bolt be pulled back at least half-way before it generates enough force to fully chamber a Redding small-base resized cartridge, yet it will easily fully accept a M193 Federal load without problems (pulled back at most 1/4 way).

M.L.

You are not trimming your cases? They grow in length ever time they are fired and will not chamber after being sized. This is DANAGEROUS and you need to be real careful.

Quoted:My Headspace is fine.  M.L.

First off, no reason to be ashamed, eveybody starting reloading needs help now and then.  

Do you have a headspace gauge?  If not, get one immediately.  If so:

What does your fired brass measure?

What does your sized brass measure?

What does the XM193 measure?

The cartridge gauge will not help you in this regard....    

I am glad you have a gauge.  Check the fit of your xm193 that works and compare to your reloads that do not.  If good, next.

You are experiencing single shot loading problems or problems from a loaded magazine?

Do you have the same problems from all your magazines?  Isolate offending magazines.  If good, next.

Single shots from an AR should be from a fully open bolt anyway so I am going to assume you meant that information to show the relative force needed.  Check bolt & lugs for a small burr that would cause a bit of drag. Polish or clean as needed.  If good, next.

Get a good bore light and check the bore.  Check for any indication that the rounds entering are impacting other than where they should be.  Check for corrosion in the chamber.  Chrome or not that could be a problem if a prior owner scratched the chrome down to the steel.  if good, next.

Carefully inspect the rounds that did not fully chamber for impact marks.  If you have loaded any soft points look for uniform or deformed tips.  Again a misalignment problem indicator.  Compare against rounds that did load correctly.  If good, next.

I am assuming that your maintenance is per specifications, but if the weapon has had a bunch of trash dirty powder shot through and you have not cleaned the gas tube and really any part of that system, then you could just not be getting your bolt carrier back far enough generate the required forward force needed to always work.  A bit of lube on the bolt and carrier might change things.  If good, next

What is the length or your cases?  You may need to trim the cases.  I would have you check out a Giraud Case trimmer.  Probably the best investment someone with two young kids can make.  I have the Dillon and the Lee and they cannot even be compared.  You load hundreds of cartridges, don't let the it's cheaper but just as good guys mislead you.  Your time with your kids is fleeting and more valuable than the cost differential.  As an engineer you will figure that out real quick.
I suspect it is the case length that is the problem , but the above issues should be ruled out first.  If the case lengths are good, next.

All the above does not cure the problem, IM me and we will meet at a range and see what's up.

BRD

If the XM193 functions properly, then chances are pretty good that your reloads are out of spec, not the chamber.  I have chamber gauges, headspace gauges, and comparators for 5.56, if you'd like to get together sometime to double-check your measurements.

BigRedDog,

Thanks for the reply.  Here's some answers to your questions/comments:

Quoted: I am glad you have a gauge.  Check the fit of your xm193 that works and compare to your reloads that do not.  If good, next.

Both, my reloads and the XM193, fit easily into the gauge.  The headspace is correct on both.  I'm trimming to 2.250"

You are experiencing single shot loading problems or problems from a loaded magazine?

Single shot problems and problems from a loaded magazine.  The bolt has difficulty closing on about 10% of the loads; and of the 90% that fit into the chamber properly, about 10% of those stick in the chamber and are VERY difficult to eject (Requiring a rubber mallet blow on the changing handle).

Do you have the same problems from all your magazines?  Isolate offending magazines.  If good, next.

I'm quite sure this is a chamber problem, not a magazine problem.

Single shots from an AR should be from a fully open bolt anyway so I am going to assume you meant that information to show the relative force needed.  Check bolt & lugs for a small burr that would cause a bit of drag. Polish or clean as needed.  If good, next.

Yes, bolt starting positions were given to illustrate relative loading forces.  I've checked the bolt face and chamber.  All look good to me.

Get a good bore light and check the bore.  Check for any indication that the rounds entering are impacting other than where they should be.  Check for corrosion in the chamber.  Chrome or not that could be a problem if a prior owner scratched the chrome down to the steel.  if good, next.

I probably ought to buy a bore light.  If anything, it will be a useful tool to have.  I haven't looked too closely at the bore.  -  I purchased the barrel new from CMMG.  It only has about 700 rounds through it (all Winchester and XM193).  As noted earlier, the chamber is clean and no burrs or wear is observable.

Carefully inspect the rounds that did not fully chamber for impact marks.  If you have loaded any soft points look for uniform or deformed tips.  Again a misalignment problem indicator.  Compare against rounds that did load correctly.  If good, next.

I'm loading 77grain matchkings (1:7 twist barrel).  I've smoked a resized cartridge and the interference appears to be occurring on the diameter between the shoulder and rim, suggesting that the diameter in this section is too large (like the RCBS die is worn out).  This is why I purchased a Redding small-base die.

I am assuming that your maintenance is per specifications, but if the weapon has had a bunch of trash dirty powder shot through and you have not cleaned the gas tube and really any part of that system, then you could just not be getting your bolt carrier back far enough generate the required forward force needed to always work.  A bit of lube on the bolt and carrier might change things.  If good, next.

I take meticulous care of the rifle.  I have cleaned the gas tube, dis-assembled bolt etc, every time that I clean it.  Bolt is pretty well lubed, and the rifle works great with M193 ammo.

What is the length or your cases?  You may need to trim the cases.  I would have you check out a Giraud Case trimmer.  Probably the best investment someone with two young kids can make.  I have the Dillon and the Lee and they cannot even be compared.  You load hundreds of cartridges, don't let the it's cheaper but just as good guys mislead you.  Your time with your kids is fleeting and more valuable than the cost differential.  As an engineer you will figure that out real quick. I suspect it is the case length that is the problem , but the above issues should be ruled out first.  If the case lengths are good, next.

Trimmed length is 2.250 +/- about .002".  Does anyone file off/remove ejector marks on cartridge rims before reloading?

All the above does not cure the problem, IM me and we will meet at a range and see what's up.

Thanks for the offer.  Perhaps I'm crying "Wolf" a little early here.  Although my bolt requires a little more force to close with the newly small-base resized cartridges than it does without any cartridge . . . I probably need to load several of them and see how they perform at the range  Hopefully, they won't stick in the chamber like the reloads with the RCBS full length die.  If I continue to have problems, I'll take you up on your offer.

Mike L.

Quoted: If the XM193 functions properly, then chances are pretty good that your reloads are out of spec, not the chamber.  I have chamber gauges, headspace gauges, and comparators for 5.56, if you'd like to get together sometime to double-check your measurements.

Yes, I have a stoney point chamber headspace and bullet comparator gauge.  I also have a stoney point cartridge headspace measuring set.  I'll post some measured dimensions this evening when I get home.

What is a 5.56 comparator?

Thanks,

Mike L.

Just one thing I have experienced:  Make sure you have your die screwed down all the way.  I have had the same issue with sizing w/ a RCBS .223 die and hard chambering in a 5.56 chamber.  

I set my die to where the handle just barely cams over at the bottom of the stroke.  It fixed the problem.  This is on a RCBS Rock Chucker.

Brian

Logem, I think I have the answer for you.  You stated that you trim to 2.260. that's a little long, the case should have a maximum length of 1.760 and I usually trim mine to 1.74-1.75.  

Of course, I realize that you meant the overall length of your loaded cartridge measures 2.260 but since you answered incorrectly in the first place, this leads me to beleive you do not trim your cases.

I am also in NW Houston and I have all the gizmos to measure reloads.  You can reach me via email.

Sig685,

Oops.  I meant that I trim to 1.750 +/- .002"  I trim every cartridge, especially since I am using once fired WW brass from brassmanbrass.com.

Overall lengths with bullets are 2.250" maximum.

I'll keep everyone's offers for help open until I try a few reloads with the new small base die.

Thanks.