6CM testing Results
- Thread starter joesr
- Start date
Just an update.
Gunsmith was extremely helpful. I do not think it's a chamber reaming problem. I pulled the barrel and found a lot of brass shavings about, which I think are coming from magazine feeding and scraping on the mag or feed ramp. I switched and ran some tests single feeding and found out that after a few rounds at 51gr that I was having a head separationsn just above the web without the nastiness up by the shoulder. Then I ran more tests single feeding at 50gr of h1000 and shot the brass 5 times without issue always neck sizing. Single feeding and being careful on extraction I didn't see these same issues up by the shoulder.
Just now I full length sized and stainless tumbled 200pcs I had only ever fire formed with 47.5gr h1000. Right off the bat I found a piece separating above the web of the case. I believe this is a bullet not seated far enough into the lands issue combined with scraping the feed ramps on the way in and dragging shavings of brass into the chamber with the brass.
Too bad I have 350pcs of fired brass that are essentially worthless and another 350 rounds loaded ready to go at a .010 jam. I think I'll stick those in a collet puller, pull them up a bit, turn the t7 to the next station and seat them right back down to jam .040 or whatever jam makes me struggle to cam the bolt handle over.
From here on out for new brass I'll be putting a false shoulder on these puppies and then going about my business. Then no wondering or worrying about having a case separate at a match or something ridiculous.
Thanks for your guys' help. Hopefully this helps some people out.
Is this verification thing for posting ever going away where I have to answer questions about typing letters that are in a picture, then minute, point, bipod in the next three boxes?
Gunsmith was extremely helpful. I do not think it's a chamber reaming problem. I pulled the barrel and found a lot of brass shavings about, which I think are coming from magazine feeding and scraping on the mag or feed ramp. I switched and ran some tests single feeding and found out that after a few rounds at 51gr that I was having a head separationsn just above the web without the nastiness up by the shoulder. Then I ran more tests single feeding at 50gr of h1000 and shot the brass 5 times without issue always neck sizing. Single feeding and being careful on extraction I didn't see these same issues up by the shoulder.
Just now I full length sized and stainless tumbled 200pcs I had only ever fire formed with 47.5gr h1000. Right off the bat I found a piece separating above the web of the case. I believe this is a bullet not seated far enough into the lands issue combined with scraping the feed ramps on the way in and dragging shavings of brass into the chamber with the brass.
Too bad I have 350pcs of fired brass that are essentially worthless and another 350 rounds loaded ready to go at a .010 jam. I think I'll stick those in a collet puller, pull them up a bit, turn the t7 to the next station and seat them right back down to jam .040 or whatever jam makes me struggle to cam the bolt handle over.
From here on out for new brass I'll be putting a false shoulder on these puppies and then going about my business. Then no wondering or worrying about having a case separate at a match or something ridiculous.
Thanks for your guys' help. Hopefully this helps some people out.
Is this verification thing for posting ever going away where I have to answer questions about typing letters that are in a picture, then minute, point, bipod in the next three boxes?
Last update I hope!
The edge of the chamber was not deburred, so the round entering the chamber from the magazine slightly askew was enough to drag the edge of the brass along the sharp chamber edge and slice/scrape it up and drag a bunch of brass shavings into and around the chamber.
I deburred with some sandpaper and hopefully all is well now. No time to shoot yet tonight, so I'll hopefully run out back after work tomorrow and give it a shot.
I am also pulling my loaded rounds and putting a false shoulder on the brass now, which seems to alleviate all issues just above the web of the case.
Don't try to PM me to get the name of the smith, it won't be shared. A few people have tried, so please don't waste my or your time. Very reputable smith and we all make mistakes some times, don't need reputations tarnished over such a simple matter.
Pic of what I'm talking about: https://www.dropbox.com/s/cl738ziugmnojen/Photo%20Jul%2022%2C%2010%2021%2032%20PM.png
You can see it sliced my fingernail right up.
The edge of the chamber was not deburred, so the round entering the chamber from the magazine slightly askew was enough to drag the edge of the brass along the sharp chamber edge and slice/scrape it up and drag a bunch of brass shavings into and around the chamber.
I deburred with some sandpaper and hopefully all is well now. No time to shoot yet tonight, so I'll hopefully run out back after work tomorrow and give it a shot.
I am also pulling my loaded rounds and putting a false shoulder on the brass now, which seems to alleviate all issues just above the web of the case.
Don't try to PM me to get the name of the smith, it won't be shared. A few people have tried, so please don't waste my or your time. Very reputable smith and we all make mistakes some times, don't need reputations tarnished over such a simple matter.
Pic of what I'm talking about: https://www.dropbox.com/s/cl738ziugmnojen/Photo%20Jul%2022%2C%2010%2021%2032%20PM.png
You can see it sliced my fingernail right up.
Wound up having to replace the barrel. At some point it must have gotten fucked. Maybe a bunch of brass wound up getting sent down the bore when it was sending shavings into the chamber? I patched the barrel clean with boretech copper cleaner letting it soak over night and then JB bore pasted it really well, but to no avail. 2MOA gun at 500. Spiral fluted Krieger 4 groove with both ends threaded and cerakoted, so that combined with the brass that was wrecked, bullets and powder wasted, and worst of all - my wasted time... it stings a bit.
To top things off while chambering two barrels with my brand new reamer he completely hosed the reamer. Top that with the other errors made over the years and I think having to eat a couple thousand dollars worth of mistakes justifies finding a new gun smith.
Reamer Shoulder: https://www.dropbox.com/s/g8dhs6tfzqp2qqv/reamer01.jpg
Reamer end of neck/throat: https://www.dropbox.com/s/z1gzxltxq8q6jd2/reamer02.jpg
Reamer body: https://www.dropbox.com/s/asjz0t9bnoeeblk/reamer03.jpg
To top things off while chambering two barrels with my brand new reamer he completely hosed the reamer. Top that with the other errors made over the years and I think having to eat a couple thousand dollars worth of mistakes justifies finding a new gun smith.
Reamer Shoulder: https://www.dropbox.com/s/g8dhs6tfzqp2qqv/reamer01.jpg
Reamer end of neck/throat: https://www.dropbox.com/s/z1gzxltxq8q6jd2/reamer02.jpg
Reamer body: https://www.dropbox.com/s/asjz0t9bnoeeblk/reamer03.jpg
All of this really sucks. I've ff many pieces of brass in my 6CM barrels without issue. I have also loaded them up to 51.5 gr. of H1000 just to see how far I could go, could have went a little more. I use Winchester brass and have 20 firings on some. In this cartridge I have found my accuracy to be at 48.7 in my 27" and 49.0 in my 30". I ff with 47.0 and have treated this round to a tee as Joe has laid out in his posts. This cartridge does everything that it was designed to do. Dave Bruno is the Smith that has done my work. There are quite a few Smiths out there that are fimilar with the 6CM that do realgood work.
Dgd6mm said:
Thanks for the support. There are definitely plenty of smiths that are familiar with it... I actually chose one that is and has been reaming 6CM for years. I suspect that many (like me) have just been fooled by him some and I'm sure he treats his own reamers with more respect than those owned by others.
All of the money and time, at least I'll come out with a barrel I can use to fireform cases I suppose. Going to make it glow
.Hand and elbow are just about healed up. I'm gonna get back out and shoot my 6CM and finish burning the barrel up, waiting for it to open up to .5 moa.I bet this happens at about 4500 rounds. This is my untreated barrel. When it does I'm screwing the nitrited 6CM barrel on and gonna run it fast with 105's.
It pretty much is nice, but you have to get out to shoot them. My BR 6CM needs to be shot also. They quit running BR watch's at Bradford, and I've been told to stay away from Cool Acres, that leaves Manatee which is 235 miles from me. All I know is I'm gonna get back to pulling the trigger more....The 6CM is very accurate and fast with great barrel life. Hey Teele1 post your 200 yard break in picture with the dime while fire forming.
For what it's worth, which ain't much, my group is ten shots. These group where shot on a 200 range were you shoot threw culvert. It is at Indianriver,Fl. there are 2 200 yard lanes with a berm that runs parallel with the 100 harder. It starts yards shy then there is a culvert which is about 20 feet then open on the backside with a berm at the target.
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