6 br case length

[6BRinNZ]

its pretty hard to get an accurate measurement to the semi rounded corners of the shoulder but it sure looks like the stretch is in the body more than anything. almost all the .020 seems to be in the first measurement its around 1.095 where it should be 1.075

If base to datum is growing then that would appear to be a sizing/chamber issue...hard to say without tools to properly measure though. You could maybe measure from base to neck shoulder junction to have a sharper point to work with (in lieu of having the tools to measure), according to the 6BR diagram on this site that is 1.2378.

Possibly if you fire the 1.58 case again without FLS you may find that the datum doesn't grow any further, and the case OAL is now only .00x longer. keep an eye on the signs for case separation, as it seems as if the body is stretching a lot, for one reason or another.

In essence you want to break the case measurements down to see which dimension is changing, (so much) so that you can fix the appropriate piece - be it sizing or otherwise.

 

[fdshuster]

bam1015: O.K., here's a thought, after reading your 1.095" vs. 1.075" dimensions.

Seems like a good suggestion to try & establish which part or section of the case is stretching, but it's naturally tough to get repeatable dimensions from the same reference point.

So, take a single edge razor blade & put a small cut mark at the rollover where the case body meets the shoulder. Another one half way between that mark & where the shoulder meets the neck. A third one where the shoulder meets the neck, and finally, another about halfway down the neck.

Using a dial caliper take & record all these lengths, from the case head. Load & fire, then take the same measurements again & compare. Seems that with the razor cut reference's you have, it should show where the stretching is originating?????

Note: I'm taking my idea from 6BRinNZ's " in essence you want to break the case measurements down"--.

 

[bozo699]

Bam,
Exactly what make and model of caliper are you using? I am not doubting your word but there almost has to be a sizing issue here or a measuring issue, the cases just can't be stretching .020 each firing, .002 but not .020 so lets break it down like Frank and Wayne has suggested but lets first find out if your tool for measuring can even be trusted, not you,...the tool. Are you using nice even pressure on the jaws? measure something of a known size 10 times and write down the measurements and see if it changes, just some things to think about.
Wayne.

 

[brxbrad]

Yesterday, a shooting buddy and myself were measuring 30/06 cases and separating them by length. After measuring 40 or 50, we went back to check ourselves. The measurments came up different. They weren't .020 different but............ You might want to check your measuring stick.

2 cents

 

[bam1015]

naw my digital calipers are in fine tune and i double and triple checked......i just bit the the bullet ,packed up the rifle and drove to knoxville (bout 30 mile one way) to a reputable gun smith ,talked it over and left it with him to fix....general consensus is my friend didnt do me no favors when he ran the new reamer through the gun , they are going to let me know for sure tomorrow but it looks like the barrel is going to have to be set back and rechambered....lesson learned

 

[fdshuster]

bam1015: You have all of us interested now. Don't let us hang, not knowing what the root cause was. Keep us informed. Thanks.

 

[hogpatrol]

bam1015: You have all of us interested now. Don't let us hang, not knowing what the root cause was. Keep us informed. Thanks.

Beginning to think it's not a 6BR or the barrel was chambered for 6BR and another 6mm reamer was used and fireforming is now taking place.

 

[bozo699]

bam1015: You have all of us interested now. Don't let us hang, not knowing what the root cause was. Keep us informed. Thanks.

Yes what Frank said, none of us has ever encountered anything like that and I for sure want to know what caused the brass to grow .020 with every firing ??? I hope your smith is way above average,....he may need to be.
Wayne.

 

[bam1015]

ill let you guys know as soon as i know anything....sometimes i think i have a cloud over my head...i never get the easy problems...lol

 

[bam1015]

been a while since my last post on the subject...some of you were interested in the outcome....i had a local smith look at it and quite frankly he just didnt seem to be all that interested in working on it...i hear he used to be quite the benchrest guy but now he seems to be into only AR stuff ..he checked headspace ,told me it was slightly off but he would just shoot it ...that was 3 weeks ago . i have been out 3 times since with different loads, working on different shooting techniques and no matter what i did it would just spray shots...cant hardly keep it at an inch at a 100.....finally got smart today and dug out my hyscore shooting sled with hydraulic trigger set up and took both it and my trusty 22-250 and strapped them in ,taking the shooter completely out of the equation....well....5 shots with 6BR were all over the place....5 shots with 22-250 and stuck all 5 in the same hole.....i guess there is still a chance its a scope problem but i doubt it , i will put scope from 22-250 on 6BR to try but frankly i think my BR is junk......been tryin for several days to call a very recomended smith in NC not TOO far from me but he doesnt answer his phone......im resigned to the fact it will need set back and rechambered.....

 

[bozo699]

Bam,
I hope you get it figured out.
Wayne.

 

[bam1015]

Well,It seems i have corralled the problem....and alas (with a bit of egg on my face)i have pretty much found it was a combination of things but mostly ME not the gun. So for all of you that chimed in thanks for the help and heres the story,so maybe another newby can learn from it...after trying to get a noted gunsmith or 2 to look at the gun...to no avail (more about that in a minute)i sucked it up and went back to the smith who i thought may have hurt the gun in the first place...explained everything and he gave me a good lesson in chambers ,headspace and pretty much showed me there was no way the chamber could be too long and still have decent headspacing.I now fully understand how this works. now this is where we come to the problem, a couple of you had asked me if i was oversizing the brass......He showed me that if i was pushing the shoulders too far then the necks would stretch out too far and thats exactly what i was doing....He showed me a simple trick to measure and keep the die sizing only to the shoulder and BINGO the gun started tighting up. Now thats not to say that a few other tips helped also....i have also started paying much more attention to my shooting rig...making sure the gun slides easily and is as close to level as possible....i have included a pic of a five shot group at 100 from todays shoot.
OH ya ..good gunsmiths....a couple of you guys recomended a smith in N.C. that i could talk to or send my gun too....i spent 2 weeks calling ...leaving messages and even talked to his wife and never got a return call.....im sure he is good ...but jeese doesnt anyone have the decency to even return a call these days even if its to say your too busy to mess with it? i spent over 10 years with my own small business and i know i could never afford to do that......just sayin....

 

[bozo699]

Well,It seems i have corralled the problem....and alas (with a bit of egg on my face)i have pretty much found it was a combination of things but mostly ME not the gun. So for all of you that chimed in thanks for the help and heres the story,so maybe another newby can learn from it...after trying to get a noted gunsmith or 2 to look at the gun...to no avail (more about that in a minute)i sucked it up and went back to the smith who i thought may have hurt the gun in the first place...explained everything and he gave me a good lesson in chambers ,headspace and pretty much showed me there was no way the chamber could be too long and still have decent headspacing.I now fully understand how this works. now this is where we come to the problem, a couple of you had asked me if i was oversizing the brass......He showed me that if i was pushing the shoulders too far then the necks would stretch out too far and thats exactly what i was doing....He showed me a simple trick to measure and keep the die sizing only to the shoulder and BINGO the gun started tighting up. Now thats not to say that a few other tips helped also....i have also started paying much more attention to my shooting rig...making sure the gun slides easily and is as close to level as possible....i have included a pic of a five shot group at 100 from todays shoot.
OH ya ..good gunsmiths....a couple of you guys recomended a smith in N.C. that i could talk to or send my gun too....i spent 2 weeks calling ...leaving messages and even talked to his wife and never got a return call.....im sure he is good ...but jeese doesnt anyone have the decency to even return a call these days even if its to say your too busy to mess with it? i spent over 10 years with my own small business and i know i could never afford to do that......just sayin....

Bam,
I am glad you finally figured it all out.
Wayne.