AR and ammo help.

[1903Collector]

Some days at the range go great, some not so great and yesterday was a not so great a day. Two problems came up that I have not figured out yet maybe you guys can shed some light.

First, I was firing my 6.8 Bushy for the first time using hornandy ammo and could not get three rounds in a row without a FTF. Sometimes it would fail to pick up a round from the magazine, or if it did it would get jammed up going into the chamber. The bolt would not lock on the last round either but does if I manually retract the bolt carrier. So it sounds like it is short cycling or a bad magazine, in fact the rifle felt sluggish when fired. I did clean it prior to use. I also used tetra grease to lube it this time and it's the first time I ever used grease and I used it sparingly so could this be the cause? When I got home I dissasemble and cleaned and could not find any cause that I am aware of. Any ideas??

Secondly, an ammo issue. Decided to take one of the 03s out for a spin. I have a bunch of the greek 30.06 ammo and when I would chamber a round I had to really force the bolt handle down to lock it up, much harder than usual like you were squezzing it in. I did not fire any of these because this sent up a flag. When I got home I chambered some Lake City 30.06 ammo and it chambered what I would consider normally, a little resistance when you throw the bolt handle down but not forcing it, same with some commercial ammo I tried. I checked both rounds on a headspace guage and they seem to be the same, Checked OAL with a comparator, maybe .005 difference. So what am I missing?

 

[bpm990d]

I think the problem with the Greek ammo is that it was just a little big. I'm pretty sure that the stuff was causing problems at Camp Perry when they issued it for the Games matches.

What exactly did you use for a head space gauge? Was it somthing that gave you a reading or did it just drop in like a wilson? If you have a RCBS precision mic. use it to check both the Greek & LC ammo and compare the reading.

My guess is that you can cure the oversized ammo problem with a body die.

B

 

[Finalygotabeltfed]

Run a new AR upper a little wet with oil for the first couple of hundred rounds to smoothe things out.

Try different ammo next shoot and see if the short stroking goes away. I'll bet it does.

On the 30.06, by headspace guage, do you mean a case guage that you drop the round into?
If you have the capability, pull a bullet on a Greek round, dump the powder and resize it in a 30.06 die and see if it chambers differently. The shoulder on the Greek may not be set back as far as the Lake City so you'll feel the slight compression in the chamber. I wouldn't worry about it. I've had .308 ammo that did the same thing and it all fired fine.
That problem went away when they were reloaded.

 

[1903Collector]

I used a Wilson guage.

 

[bpm990d]

An RCBS Precision mic or Mo's gauge will allow you to take a relative measurement and help you set up your die so you are not pushing the shoulder back too much. It basically gives you a numerical reading. I think you might be able to do this with a Wilson die if you have a depth micrometer or a dial caliper with an ability to make a depth measurement from the case head to the surface of the wilson die but I'm not positive. If you have a bunch of Greek stuff, you can probably just bump the shoulder with a Reading body die to get it to fit in the Springfield.

B