Bergara short chamber

[whatsupdoc]

I can pretty much guarantee that when they were making the prototypes of the Bergara rifle some machinist said "¿Por qué diablos no hacemos la recámara plana?" or
"why the heck dont we make the breech flat" . Then some engineer had a reason as to why.

 

[LVLAaron]

Make it flat

Absolutely. Someone got "clever" with the CNC program on that one.

 

[gero]

If possible measure the datum of the go gauge and brass your using.
As long as go gauge is longer than virgin brass your at least in a workable range.
I have seen a few go gauge’s that were incorrect from a certain popular manufacturer.

What are you getting for case expansion now after firing now?

I measured 5 random new loaded rounds (same lot) and 5 fired cases from the same lot as I used last session with a comparator. The fired cases grew between .003 to .0045.

 

[tobnpr]

And looks more annoying than it needs to be to machine

Like a recessed target crown on steroids...

 

[SKWERLZ]

I measured 5 random new loaded rounds (same lot) and 5 fired cases from the same lot as I used last session with a comparator. The fired cases grew between .003 to .0045.

More than I like but quite acceptable for a production rifle
Now compare those against your go gauge

 

[whatsupdoc]

I measured 5 random new loaded rounds (same lot) and 5 fired cases from the same lot as I used last session with a comparator. The fired cases grew between .003 to .0045.

You should remove the primers or push them in before measuring, they
will skew your measurements.

 

[gero]

You should remove the primers or push them in before measuring, they
will skew your measurements.

Thanks, after depriming the same cases as last nite, five cases are 1.615 to 1.6155.

More than I like but quite acceptable for a production rifle
Now compare those against your go gauge

So whatsupdoc mentioned that cases should be deprimed before measuring. It appears that the difference between fired cases and the go gauge (1.715) after depriming is 0.1...10 thou...seems like a lot. Maybe it does need to take a trip to the factory.

 

[SKWERLZ]

You should remove the primers or push them in before measuring, they
will skew your measurements.

True

 

[whatsupdoc]

Thanks, after depriming the same cases as last nite, five cases are 1.615 to 1.6155.

So whatsupdoc mentioned that cases should be deprimed before measuring. It appears that the difference between fired cases and the go gauge (1.715) after depriming is 0.1...10 thou...seems like a lot. Maybe it does need to take a trip to the factory.

What tool are you measuring your fired cases with?

 

[Mdhmsmith]

Unless there’s a decimal and a zero missing somewhere those numbers don’t compute.

 

[gero]

True

What tool are you measuring your fired cases with?

Unless there’s a decimal and a zero missing somewhere those numbers don’t

I had a decimally induced brainfart this morning. The go gauge measures 1.6175 and avg fired case 1.6150 so looks like .0025.

What tool are you measuring your fired cases with?

Hornady comparator

 

[gero]

I went to the range today. I wanted to verify that the poi hadn't shifted and to function test the Bergara after having adjusted the headspace. I found that the poi had shifted, about 18"up and 9" to the right. After getting zeroed, shot these groups with factory FGMM @100 yds I may have moved the headspace only 2 or 3 thou. Math might be a little off on the second group. I think .403 moa?

 

[Old Navy]

18"up and 9" to the right is a lot. Something else went on there.

 

[Dusty Stevens]

18"up and 9" to the right is a lot. Something else went on there.

Not surprising on a factory nut barrel. It will still shoot the same just in a different spot

 

[Eagle Six]

I went to the range today. I wanted to verify that the poi hadn't shifted and to function test the Bergara after having adjusted the headspace. I found that the poi had shifted, about 18"up and 9" to the right. After getting zeroed, shot these groups with factory FGMM @100 yds I may have moved the headspace only 2 or 3 thou. Math might be a little off on the second group. I think .403 moa? View attachment 1420148

How was the function part of the test, you didn't say?

 

[gero]

How was the function part of the test, you didn't say?

Function is fine. Actually, I am thinking the Berg made the smallest groups of its life so far. I dont know if resetting headspace contributed to that, because I also got new cheaters a couple of days ago. I also checked the headspace on fired brass and compared to brass fired before I changed anything. It looks like the latest fired brass is about .002 or .003 longer in the headspace than the previous.

 

[Old Navy]

Not surprising on a factory nut barrel. It will still shoot the same just in a different spot

It would be on any one of three Savages Model 12 target actions I have.
Edit: Just sold one for half of what I paid for my Lone Peak Razzor.

 

[whatsupdoc]

I know that guys were removing the barrels from RPR and putting them back on
and the rifles would shoot tighter groups. Strange, maybe the threads had
better contact after removing and reinstalling the barrel.

 

[ptboat]

I can pretty much guarantee that when they were making the prototypes of the Bergara rifle some machinist said "¿Por qué diablos no hacemos la recámara plana?" or
"why the heck dont we make the breech flat" . Then some engineer had a reason as to why.

I think when it came time to chamber the first barrel .it was Friday at noon.the boss said we need this done today before you go home.the tech says God dam it here we go again.so he chambers barrel all pissed off.screws action on realizes he cut shoulder back to far.bolt hits end of barrel.so he cuts that pretty breach face on it so barrel would work and he can go home.then boss says what's this breach face cut like this for? Tech smiles as he punches out for the week it's for feeding issues.lol