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Need help with 6AR

Hotshot

Silver $$ Contributor
Several years ago I bought a used upper in 6AR. It came with dies and brass. I also bought some used brass another member had fired in a different rifle. After a brief struggle, I put it all in a corner of the closet and basically forgot about it.
My problem is that I can't chamber the loaded rounds. The barrel and dies are from AR Performance. The dies(RCBS) and chamber don't seem to match up.
It would be wonderful if someone could send me a couple brass. I'd like a fired one from a 6AR chamber and a resized one that is ready to load. It would help me determine if I have a wrong chamber or a wrong die. I would appreciate the help and will be happy to pay for the brass and shipping. Regards, Mark
 
Update. Bat sent me 3 brass. Fired, prepped and new. The fired brass would not chamber, no surprise. The prepped brass which has been fired and resized by him would not chamber, almost but not quite. I necked down the new brass in my die and it did chamber. Yay! I sized 100 new Hornady brass with my die. 55 will chamber 45 will not. I'm going to fire some rounds tomorrow then resize them with my die and hope they will chamber. I can't find a consistent measurement to explain the difference between the rounds that chamber and those that don't. I have trimmed and turned necks, no difference. I am using RCBS shell holder 6. Could the number 32 shell holder make this difference?
 
Update. Bat sent me 3 brass. Fired, prepped and new. The fired brass would not chamber, no surprise. The prepped brass which has been fired and resized by him would not chamber, almost but not quite. I necked down the new brass in my die and it did chamber. Yay! I sized 100 new Hornady brass with my die. 55 will chamber 45 will not. I'm going to fire some rounds tomorrow then resize them with my die and hope they will chamber. I can't find a consistent measurement to explain the difference between the rounds that chamber and those that don't. I have trimmed and turned necks, no difference. I am using RCBS shell holder 6. Could the number 32 shell holder make this difference?
Ink the case up and it should show where it's tight.
 
I bought a 32 shell holder. No difference. I inked up a couple brass one that would chamber and one that wouldn't. Nothing definite. Slight touching on shoulder shows on both maybe a little more on the no chamber one. So very little I don't think it's that.
 
I bought a 32 shell holder. No difference. I inked up a couple brass one that would chamber and one that wouldn't. Nothing definite. Slight touching on shoulder shows on both maybe a little more on the no chamber one. So very little I don't think it's that.
That ink test is pretty definitive in that if the case is tight, it'll show where.. but to contact area can be super thin. You likely need to cycle the bolt up and down a few times to show it more clearly. If you saw a mark at all, that's likely where the problem is.
Of course if the problem could be unrelated to the brass, that's different story but I'd still bet ink will show the interference area and I'd still bet it's something with the brass.

It might be hard to see but I bet it's there. I'd give it another try but work the bolt a bit. If the case rotates at the boltface, it will only leave a faint mark elsewhere and it can be razor thin and hard to see.
 
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Update. Bat sent me 3 brass. Fired, prepped and new. The fired brass would not chamber, no surprise. The prepped brass which has been fired and resized by him would not chamber, almost but not quite. I necked down the new brass in my die and it did chamber. Yay! I sized 100 new Hornady brass with my die. 55 will chamber 45 will not. I'm going to fire some rounds tomorrow then resize them with my die and hope they will chamber. I can't find a consistent measurement to explain the difference between the rounds that chamber and those that don't. I have trimmed and turned necks, no difference. I am using RCBS shell holder 6. Could the number 32 shell holder make this difference

Update. Bat sent me 3 brass. Fired, prepped and new. The fired brass would not chamber, no surprise. The prepped brass which has been fired and resized by him would not chamber, almost but not quite. I necked down the new brass in my die and it did chamber. Yay! I sized 100 new Hornady brass with my die. 55 will chamber 45 will not. I'm going to fire some rounds tomorrow then resize them with my die and hope they will chamber. I can't find a consistent measurement to explain the difference between the rounds that chamber and those that don't. I have trimmed and turned necks, no difference. I am using RCBS shell holder 6. Could the number 32 shell holder make this difference?
The resized brass I sent had the shoulder bumped .001" to .0015" from having been fired in my chamber. I suspect his chamber is just a squish shorter than mine.
 
That ink test is pretty definitive in that if the case is tight, it'll show where.. but to contact area can be super thin. You likely need to cycle the bolt up and down a few times to show it more clearly. If you saw a mark at all, that's likely where the problem is.
Of course if the problem could be unrelated to the brass, that's different story but I'd still bet ink will show the interference area and I'd still bet it's something with the brass.

It might be hard to see but I bet it's there. I'd give it another try but work the bolt a bit. If the case rotates at the boltface, it will only leave a faint mark elsewhere and it can be razor thin and hard to see.
I re-read my post above and it was a mess. I tried to correct the several grammatical mistakes. Hopefully it makes more sense now than before. Sorry if it was a confusing mess before. Bottom line is, that ink test is just like the target...It doesn't lie but it might be hard to see, so work the bolt a bit when you do it again so it leaves a good mark.
 
I had that problem in one of my 6AR's. My solution was to purchase a small base die for my 6.5 Grendel, pull the expander ball and run the 6AR brass through it. I also found that all 3 of my rifles had too much headspace. A set of Redding #12 competition shellholders rectified that problem.
 
I had that problem in one of my 6AR's. My solution was to purchase a small base die for my 6.5 Grendel, pull the expander ball and run the 6AR brass through it. I also found that all 3 of my rifles had too much headspace. A set of Redding #12 competition shellholders rectified that problem.
Had to do the same with my main match rifle. Would have 2-3 rounds a match that wouldn’t feed. Small base 6.5 Grendel die took care of that.
 
With all this good advice I think I have this problem figured out. Bat gave me a hint on checking headspace thinking I might not have enough. Opposite of that I have way too much so I will have to look for the competition shell holders. I inked them up again as suggested by g&g and there is some contact on the body. Very little but definitely there. I discovered that the brass that chambers is a couple thousands less than the no chamber brass at 1/4 inch below the shoulder. I will try the SB die next as soon as I can find one. Thanks everyone for your good help.
 
With all this good advice I think I have this problem figured out. Bat gave me a hint on checking headspace thinking I might not have enough. Opposite of that I have way too much so I will have to look for the competition shell holders. I inked them up again as suggested by g&g and there is some contact on the body. Very little but definitely there. I discovered that the brass that chambers is a couple thousands less than the no chamber brass at 1/4 inch below the shoulder. I will try the SB die next as soon as I can find one. Thanks everyone for your good help.
I use a redding 6.5 Grendel full length bushing die and it works well with my reamer. Part number is 77478 fwiw. If it'll help, I can measure sized brass vs fired at the shoulder, at base/.200 line, as well as post my reamer print. What does your brass measure there? I've never used the rcbs so I have no idea of it's dimensions but this should tell you whether or not the redding die will fix your sizing troubles without going to a small base die. Please use a good micrometer rather than calipers if available and measure in tenths as best you can.
 
I use a redding 6.5 Grendel full length bushing die and it works well with my reamer. Part number is 77478 fwiw. If it'll help, I can measure sized brass vs fired at the shoulder, at base/.200 line, as well as post my reamer print. What does your brass measure there? I've never used the rcbs so I have no idea of it's dimensions but this should tell you whether or not the redding die will fix your sizing troubles without going to a small base die. Please use a good micrometer rather than calipers if available and measure in tenths as best you can.
With a pretty good digital caliper: I measure .427-.4275 at the shoulder and
.437-.438 at the base/.200 line. These are fired brass that I have resized in my 6AR die. These will chamber but they are tight.
 
Yeah same here. I resize all my 6AR rounds with the same die and some just need a bit more shoulder bump to be able to chamber in my rifle. So I've made it a habit to bump them all with the same force and I even run them through the chamber just to make sure.
 
With a pretty good digital caliper: I measure .427-.4275 at the shoulder and
.437-.438 at the base/.200 line. These are fired brass that I have resized in my 6AR die. These will chamber but they are tight.
Really needs to be more accurate than calipers are designed/intended for. Even the best calipers are not intended for precise measurements, in tenths, regardless of their resolution. This is probably the most critical measurement there is relating to firearms. Or at least the one that requires the most precision. Calipers are like guessing in this application.
 

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