223 Failure to Chamber

[GooseGun]

I just reloaded some 223 with 55gr v-max. I'm fed them through my FN SCAR 16 and they shot fine but when I chamber in a AR the bolt fails to lock and will get stuck. I'm resizing with a RCBS AR T/C SB die and a Hornady LNL AP press. Without measuring them with my caliper I think what might have happened was the resizing die was dropped to the shell plate and forgot to screw down an extra 1/2 turn which may have made the case a tad bit long. Oh, I also trim neck with the World's Finest Trimmer which I set off a 5.56 factory unifired casing. My SCAR headspace might be a little more relaxed than an typical AR. Any thoughts?

Have not had a chance to run a caliper on the casings yet.

Thanks for you help.

Derek

[wild_weasel]

It could be a dirty chamber in your AR. Try scrubing it out with an AR chamber brush.

Cheers,

[XDRoX]

Most likely you just need to turn your die down a little more. It's not the the cases are too long, it's that they are not completely sized all the way to the base. They are slightly too big at the base.

[gau17]

Most likely you just need to turn your die down a little more. It's not the the cases are too long, it's that they are not completely sized all the way to the base. They are slightly too big at the base.

+1 check your headspace. You should look into getting a dillon or Wilson case gage.

[davegar1]

Case lenght issue.

[ExtremeX]

Check your headspace.

Make sure your dies are setup correctly.

Set your trimmer to the correct length off your cases you plan to reload after the shoulders have been bumped back the correct amount. Don’t just use a factory case and assume it’s all good if that’s what you are doing.

Check everything with calipers.

[NorCalTommy]

Had a similar problem. Ran the loads through a full length resizing die and that fixed it.

[GooseGun]

Thanks!

Someone I spoke to recommended they use a neck sizer die at the last stage as a solution to this problem. Seems to only happen in certain rifles. Go figure.

[NoNOS67]

Thanks!

Someone I spoke to recommended they use a neck sizer die at the last stage as a solution to this problem. Seems to only happen in certain rifles. Go figure.

I can't see this as being necessary under any circumstances. If your dies are set up properly, you should be fine.

[ExtremeX]

I can't see this as being necessary under any circumstances. If your dies are set up properly, you should be fine.

+1 ^^

[kmca]

Does the bullet in the round that won't chamber have any rifling marks on it? Could be the OAL. The FN may have a little more free bore than your AR.

[jameshenry]

Use a case gage to help set up your dies.

[GooseGun]

I did purchased a case gauge and borrowed one until it comes in. Great tool.

[NoNOS67]

I did purchased a case gauge and borrowed one until it comes in. Great tool.

What was the result when you checked one of your reloads?

[ar15barrels]

My SCAR headspace might be a little more relaxed than an typical AR. Any thoughts?

Have not had a chance to run a caliper on the casings yet.

I would bet on the scar headspace dimension being longer.
Measure the headspace length of some fired cases from each gun and report back.

The dimensions should be around 1.467" so if you are getting drastically (more than +/- 0.010") dimensions, there is something wrong with your measurement method.