Lands marking bullets

On my hand loads the book specs a COAL of 2.250 (223 Rem 55gn V-Max). Mine average 2.249. I had a barrel that was marking bullets nearly all the way back to the casing and was jamming it in the lands so far it was hard to eject the unspent round. There were other issues with that barrel so it got returned to the maker. I was curious so I loaded the same round in another new barrel from a different maker and this one also marked the bullet but not so far back. I used the same round and measured it at a COAL of 2.249. Placed that same round in my old daily use barrel and it was fine. What are the odds of getting two barrels from bifferent makers that do this? Or am I missing something?

2 questions

1- Are you sure its the lands marking the bullet and not a feed ramp etc.?
2- Are you measuring and seating to COAL or from the ogive?

1. Yes it's the lands. Have to put some good muscle behind the charging handle to get the unspent round out of the chamber.

2. COAL

One more bit of info. Both these barrel are brand new.

I tried the marker method once and didn't trust it. Here is what FiremanJG told me to do and it works perfectly:

Size and deprime a case.

Take a dremel tool with a cutoff wheel and cut a slit in the case mouth like the picture below. I only made one cut straight through both sides but this is the only pic I could find online.

Now just stick a bullet the casing enough to kind of hold it in place.

Insert it into the gun, close the bolt, and eject it.

Repeat this several times and write down the measurements. You should get consistent measurements.

It also gives you more consistent measurements if you measure to the ogive using a comparator tool. I bought the Hornady one. Soft point bullets can easily have variations in the tips so COAL may not yield precise measurements every time.

Never mind. Didn't catch the AR part. I'm no help. I just use book COAL on my 5.56 and haven't had issues.

Will give it a try. Thanks!

I don't know if it will work in an AR. The forward slamming force may jamb the bullet far into the rifling. I've never tried it. Plus they wouldn't fit in a standard Pmag without some modification anyway so I never saw the point. I get half to 3/4" groups seated to book COAL anyway.

I never have either until these two barrels.
The first one is a Stag Arms (which they are replacing due to multiple manufacturing errors, take note I will never deal with SA again)
And the second one is a Brownells special. It marks far less than the SA.

Is the marking you are referring to, all the way around the circumference of the bullet? Or is it in one place on the bullet? If the loaded round has some run out (out of round), it will show rifling contact on one side of the bullet, but not all the way around the circumference of the bullet. Also, when I am chamber checking a round in an AR platform, I do feed it from the mag. Mag feeding will scratch up the bullet when feeding into the chamber.

I was wondering about that but am willing to try most anything in order to do it right and get better.

My daily use M&P 15, the cheapest rifle on the market at the time, has never given me any trouble and am getting half inch by the book as well.

You can count the lands all the way around. Tried it with factory rounds as well and got the same results.

Yes, well that's problem #1. Don't get me started on Stag and their accuracy guarantee. I have seen several of their barrels have major defects on their accuracy guarantee rifles. Sure, they replaced the barrel, but why did it leave the shop to begin with shooting like that?

Exactly.

You could see where they started to drill the taper pin holes in the gas block when mounting it to the barrel, backed off, started again and still got it wrong.

Not to derail your thread too bad but I have been very impressed with my Rock River upper. I have the 16" model of this:

http://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_id=271

If you decide to give up and start over you might try it or one of their barrels.

Two things to mention. First is that you can use the method, with your cleaning rod, that Nosler reloading books (older versions had it) suggested for measuring for max COAL length. I used it for years. Second is that chambers can vary quite a bit in size/length. Recently I wanted to load up some 63 gr Sierra SMP bullets for my 223, which has an aftermarket Benchmark barrel. Prior loading for the previous barrel was at Lyman 49th COAL suggestion, which I believe was 2.26 inches (don't have the book with me at the moment). So, without going through the measuring process, I loaded up some rounds, which jammed into the lands. I had to stop and do what I should have done first, which is measure for max COAL. I adjusted the length of the remaining loads and all is well.

You could always try taking the upper off the gun, by hand place the cut, deprimed case w/ bullet into the chamber, push the bolt carrier group back home from the back of the receiver, and measure the COAL that way.

I can't imagine why that shouldn't work.

After the SA barrel gets replaced, it's on to my 6.5 Creedmoor builds for the time being.
I've always liked RR.

It works. You just have to ease the bolt closed, then let go the last inch. If it doesn't close, use the forward assist.

No forward assist, you'll have to let the spring do the work, and then the bullet might lurch forward giving you a false reading.

The case should stop on the shoulder even under pressure. If the lands are marking the bullet, there is an issue with either the ammo, the throat, or both.

Land markes on the bullet just means the bullet is seated out too far. If this is happening with factory ammo, I'm going to blame a chamber problem.

If i remember COL for military ammo is... 2.230... 55 and 62 gr ammo.

I am wrong its 2.260 !!!!

I did have a bad sizing die once but that ammo jammed in 14 out of the 15 ARs i have, during manual extraction !

Have done this trick for several different calibers and it works like a champ. Cheap, relatively easy and effective.

Btw, as said elswhere, measuring to the Ogive will give much more consistent results than measuring COAL off the meplate.

I Tried that,,, the bullet 98% of the time sticks in the rifling's and i eject an empty case !

Don't think I have had a bullet stick with this method but 3 or 4 times with this method, and it is an easy tap out with a cleaning rod. You can also drill and tap the case for a threaded rod, aka these setups were around before the gauges you can buy for the same purpose.

If the bullet sticks in the rifling, and an empty case ejects, it's loaded way too long. Shorten the length of the loaded bullet and try again. Write down "before chambering length" chamber it, write down "after chambering" length (at the ogive). With practice, about five tries and you know exactly where the lands are.

Hmmmm .

This is all to weired any way ! Every AR-15 maker i know uses a ton of free bore any way !

You cant make a bullet touch the riflings and still have it fit inside the magazine !!!!

That's true until it's not.

REALLY?
Not to mention 2 barrels from two different suppliers !!!!
Something aint Kosher !!!!