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Hello to all. Question reguarding copper splinters.


Brandon

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Brand new to the forum. Thanks for any help that may be given. I have a diamond back AR10, 16 inch heavy barrel, with a 1/10 twist. I loaded 178 grain amax bullets on never fired lapua brass, with 44 grains of varget powder. My hand loads shot fine, however I shot 20 rounds of federal fusion and that's where the fun began. It would not pattern at 100 yards with the federal shells. It left copper slivers on my bolt and the mouth of the bore. My gun was also leaving 2 little grooves just below the collar of the shell. Any one have any idea on what may be going wrong? Thanks again for any help as I'm brand new to the AR10 world and the world of hand loading. 

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11 minutes ago, Brandon said:

Brand new to the forum. Thanks for any help that may be given. I have a diamond back AR10, 16 inch heavy barrel, with a 1/10 twist. I loaded 178 grain amax bullets on never fired lapua brass, with 44 grains of varget powder. My hand loads shot fine, however I shot 20 rounds of federal fusion and that's where the fun began. It would not pattern at 100 yards with the federal shells. It left copper slivers on my bolt and the mouth of the bore. My gun was also leaving 2 little grooves just below the collar of the shell. Any one have any idea on what may be going wrong? Thanks again for any help as I'm brand new to the AR10 world and the world of hand loading. 

Brandon welcome to the forum I'm unsure the root of your problem but someone should have an idea soon. In the mean time feel free to post up In the intro section and tell us about yourself

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26 minutes ago, mineralman55 said:

Put up some pics so we can see the grooves and splinters. 

44 grains of Varget under a 175 is a very stout load for a 7.62x51. You sure you want to be that high?

Thanks for all the replies. In my book that I'm using it says 41 to 45 grains. In my research I found that 44 grains was a good load to shoot. If I need to go down in powder I can. Will try and post a pic of the case. 

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Just now, sketch said:

New rifle will shed brass for a while. You saw copper slivers?

It looks like little slivers to me. Its in the neck of the bore where the bolt pushes the round into the bore. Just seems weird that yesterday I didn't have any of this with my hand loads, and today when I shot the fusion rounds I ended up with junk in my bore. 

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3 minutes ago, sketch said:

Ok i see something. Make/ model / history of rifle? Much to be determind from a vague discription. If you want an assesment from the internet be warned your info will give you the answer. But your in good company. 

Diamond Back db10 308. 16 inch heavy barrel with a 1/10 twist. Bought brand new in the box. Put 60 rounds in it yesterday and never had a problem. Cleaned and lubed and reassembled correctly last night for more range time today. Everything lubed that should be lubed. Had 0 shavings yesterday, but I only shot my hand loads yesterday. Thank so much. This was 100 yards yesterday. After the first 2 we're low I got it pretty close. 

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What about the fusion rounds today?

 

I'm jumping in here uninvited, hope I can help. How many total rounds of each down range? Did you follow a break in procedure for the bore, run a patch after each shot first 10 or 20 rounds? Why are you shooting fusion bullets?

Did you use a full magazine and shoot all the rounds each loading? You haven't shot any bore lapping rounds yet? Don't for a while. Are you using any special bore cleaning solvent like Benchrest Hoppes? Which is a copper anti-fouling solvent. It attacks copper. Don't use it without knowing the side effects.

I really haven't seen anything specially bad with your case picture but that 44 grains of power seems a lot. However I would not be surprised if you shoot some basic beginning pressure FMJ loads the slivering stops..

 Has the gas key and inside of the bolt shown any slivers?

I know this seems like a lot of questions. Don't read anything bad into them.

 

 

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I'm thinking the Fusion rounds are crap. I bought 6 boxes of 6.8spc of it on a closeout @ WallyWorld for $11.99 each and all of it grouped like crap out of 2 different guns. So DONT worry about it. The brass is good  !

On your load of 44gr , there is a reason it says starting load ! Start there ! Then work up ! Nuff said ...!

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7 hours ago, mrmackc said:

 

What about the fusion rounds today?

 

I'm jumping in here uninvited, hope I can help. How many total rounds of each down range? Did you follow a break in procedure for the bore, run a patch after each shot first 10 or 20 rounds? Why are you shooting fusion bullets?

Did you use a full magazine and shoot all the rounds each loading? You haven't shot any bore lapping rounds yet? Don't for a while. Are you using any special bore cleaning solvent like Benchrest Hoppes? Which is a copper anti-fouling solvent. It attacks copper. Don't use it without knowing the side effects.

I really haven't seen anything specially bad with your case picture but that 44 grains of power seems a lot. However I would not be surprised if you shoot some basic beginning pressure FMJ loads the slivering stops..

 Has the gas key and inside of the bolt shown any slivers?

I know this seems like a lot of questions. Don't read anything bad into them.

 

 

I did run a patch after 20 rounds. I also used a little oil as I didn't want it to run dry. As I mentioned earlier, my hand loads shot great without any problem. I had bought a couple boxes of fusion to hunt deer with and never used them. I took them to the range to see how they shot. The fusions are shorter in oal than my hand loads. On my fusion rounds I did not load a full mag. I loaded 10 each time. The gas block doesn't show any signs of slivers but the bolt had some around the extractor. Most were located at the beginning of the bore. The cleaners I am using are pictured below.

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Here are the Sierra and Hodgdon loading charts for 175 grain rounds in .308. I've found Sierra's data to more closely represent the "real world" (alright, mine) than Hodgdon's data. I think your loads are way too hot. Back them down to ~40 grains and start there. Always a good idea with a new rifle to start with appropriate commercial rounds, then move to reloads and start low and increase the charge until you find your optimum load.

Vertical grooves in the brass neck are likely debris in the chamber. Circumferential grooves in the neck are likely an imperfectly reamed/finished chamber. Keep the bolt lubed with oil, not grease for break. I found I needed at least 120+ rounds before a new 308AR breaks in well. Good luck.

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