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How much were the groups opening up before it started key holing? That looks like an 8 inch target, and I know this probably isn't deliberate aimed fire, but that makes this spread is about 24 MOA... If it's doing it with no FH, barrel is simply done. 5K rounds seems fast, but a non chrome lined barrel is definitely going to wear faster than expected, especially with accelerated firing.
"SEND IT" happens to be my trigger words...
All shooting has been done of paper, cardboard, some sort of target.
The vortex FH is brand new and I was having the same issue with the dynacomp that I had been using even before all of the "sesame seed holing" began.
-BTO-
The groups weren't really opening up that I saw. That target was shot off hand from about 25yds with DD fixed iron sights (love em) and it was not deliberately aimed. Shot off bags with the iron sights I can still get 5rds in about a 1.5" group at 50yds. Granted I'm not sharp shooter but I think that's a respectable group for factory ammo.
-BTO-
I was goin through the pics of targets that I have and found this one.
This is from around the time I started to see the key holing begin. As you can see there are a number of holes showing proper bullet impact and then a bunch of profile impacts.
I believe this was 2 magazines worth sent down range and I began to assume that the normal impacts were from the cold barrel and then as the barrel began to heat up then the tumbling began.
Any thoughts on this? And again I am really appreciating all of the input and knowledge that y'all are offering up!
-BTO-
A word on choosing a barrel or upper. There are more factors at play than just the material the barrel is made out of, although that is important too. I will mention two important ones.
Gas port size- you don't want your rifle to be overgassed. It can cause problems down the road. Most companies do over-gas their rifles because they want them to work with crappy ammo. Which is the wrong fix to an almost non problem. Pick a company that you are assured has the proper gas port size. DD and BCM are two of them.
Quality control.- You want a company that has high standards here. Very many companies do not invest in checking chamber dimensions, bore uniformity. They do not high pressure test nor Magnetic particle test their barrels. ON the other hand, I know that BCM meticulously inspects every upper, lower, barrel, bolt, carrier, etc that is made for them, and HP/MP EVERY barrel and bolt.
Since I learned the efforts Paul at BCM goes to to make sure his product is the best it can be, I have changed my outlook on choosing a rifle. There are a few I trust more than others. BCM, DD, Nov are a few of them. Sadly most companies don't put the effort. Including a few mentioned on this thread.
Last edited by Shiz; 03-04-14 at 22:25.
I have a 7.5" 5.56 barrel used on an M16 lower as a 'blast O tron' that I've replaced. It likely had 5k to 10k through it (as well as 22LR). It started key holing like yours. The rifling is almost non-existent. The gas port is also flame cut on the inner bore significantly.
Either your barrel is somehow copper fouled reducing the effect of existing rifling or the rifling is worn down.
Don't use a suppressor on this either...
I'm guessing the barrel is toast. Sorry.
Key-holing bullets without a muzzle device of any kind indicates bullets are too heavy or simply that the barrel's toast.
Low-grade mass-produced barrels coupled with abuse can ruin a barrel in less than 2,000 rounds. I've seen some custom barrels from mass blanks do screaming tight groups for about 1200 rounds before any kind of precision goes completely out the window.
Ok guys. Just placed my order for one of BCM's BHF 14.5" KMR uppers. Also gonna get one of thier bCG's. Heard nothing but good stuff about BCM so gonna take the plunge. Update and range report to come shortly, hopefully.
-BTO-
-BTO-
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