CBC test for Farkle

[bubbasks]

Tested out those rounds you asked. Here are the results. 2-4 shot groups off the sled and 2 cycle test rds.

Chrono:2800,2801,2812,2772,2747,2800,2791,2812,2795,2812.

http://rs1350.pbsrc.com/albums/p769/BubbaLR308/IMG_20131012_124422_013_zps3ab1d33f.jpg~320x480?t=1381620316

http://rs1350.pbsrc.com/albums/p769/BubbaLR308/IMG_20131012_124428_968_zps2556ffc2.jpg~320x480?t=1381620311

[FaRKle!]

Hrm, that seems perfectly normal/reasonable for M80. I wonder why I've been getting so many popped primers with it. Maybe luck would have it that you just happened to get 10 good rounds... lol

 

Thanks for doing the test!

Edited October 13, 2013 by FaRKle!

[bubbasks]

I didnt get any popped primers or even any pressure signs. U wanna borrow my headspace guage?

[FaRKle!]

I didnt get any popped primers or even any pressure signs. U wanna borrow my headspace guage?

 

Hrm, maybe. Although I haven't had any issues with the CBC 168gr stuff or your privi.

[bubbasks]

Ill make u some of them 175 smk's at 2760ish i screwed up on lol jk. Those suckers skurred me a bit

[FaRKle!]

Ill make u some of them 175 smk's at 2760ish i screwed up on lol jk. Those suckers skurred me a bit

 

Is that measured at the muzzle or if not, how far down? I know M118LR is spec'd at 2580fps, but that's also measured like 90yds from the muzzle.

[bubbasks]

Basically muzzle. 5ish yards

[bubbasks]

Those blew the primers out and streched the pockets to where any new primer would just slide in and fall out

[Boerboel guy]

I shot 50 rounds of this m80 today. All from the same box.

The first 20rd mag fed, fired and ejected flawlessly. All the brass looked fine.

The second 20rd mag full short stroked every single shot, jamming every time. I figured I had a bad mag after the first 6 shots so I dumped the ammo and stuck it in the other known good pmag. Same short stroking issue. The ejected brass, if it actually ejected fully would fall right beside me. All of that brass had more aggressive extractor marks on it. It all had flattened primers.

The last mag of 10rds fed, fired and ejected perfectly again, just like the first mag full.

22 of the cases have flattened primers and heavy extractor marks. The rest look perfectly fine.

I also ran 80rds of lake city after that without a single issue.

I only had this one box I bought to test for range ammo but won't be buying it again. This rifle hasn't had a single issue with anything else.

Edited October 20, 2013 by Boerboel guy

[N Jensen]

_{Sounds like the ammo is just to hot for your rifle. I believe the short stroking of the action is due to the excessive pressure causing the case to stick in the chamber. All the energy of the bolt carrier trying to unlock and extract the case has been expended and there is not enough energy left for a full stroke of the action. As you shoot more ammo and things get hot, the problem becomes apparent do to heat expansion of the metal and carbon build up in the bore. The last time I shot LC ammo M 118 in my rifle I bent the bolt stop while federal match worked fine, no issues ever. The difference in ammo is a lot. First the LC ammo uses a tar like sealant around the bullet and the neck of the case. When this ammo sits a for years the neck tension becomes super high compared to Fed match ammo without the tar sealant. Then a 173 FMJ compared to a 168 MK one is harder than the other.}

 

_{If you have a bullet puller try see how much effort it takes to pull a bullet compared to Fed match ammo. I'm sure LC M-80 ammo is made the same way with sealant. I figure the high pressure comes from the extra force needed to push the bullet out changes the pressure curve, it peaks a lot quicker than normal, resulting in stuck cases . In my case, very high BCG cycle velocity that it produced and bouncing off the buffer and slam back into my bolt stop. Much harder than what fed match would do..}

 

_{I would suggest you try and seat the bullet deeper into the case, say .015 to .020 and break that seal and give the bullet a chance to bust out of the case before getting jammed into the lands of the rifling. Seating bullets a little deeper was used a lot on M 118 ammo during the 600yd slow fire stag to help lower the SD in velocity of the ammo and keep vertical displacement between the 10 ring instead of the nine ring.}

 

_{I was also curious if none military ammo work fine in your rifle.}  

 

_{Give a try, not hard to due and takes very little time to do it.}

Edited October 20, 2013 by N Jensen

[Boerboel guy]

I've run Federal, Lake City, Barnes, Winchester of multiple types, Remington, and lots of Freedom munitions ammo without issue. The only other ammo that has ever flattened a primer in my gun was the Federal 7.62x51 tracer. The CBC is inconsistent enough and I've seen enough pressure complaints now that I won't be bothering with it again. It is also the first ammo to ever cause a failure in my gun, let alone repeated consistent failure. 

[N Jensen]

Sounds good. Shoot what works.

[Boerboel guy]

Just tried another box of the CBC. Same issues. Some of it is loaded way hot and again caused extraction issues. Recoil was noticeably harder and faster than the ppu.

As far as I'm concerned this is hands down the shittiest ammo I've ever shot, beating any of the Russian steel by a wide margin as it races to the bottom of the pile of crap not worth shooting. I would never consider using this ammo for anything other than failure drills. If CBC is in fact Brazils manufacturer for military ammo I pity those soldiers. While they're busy trying to fix a ton of jams and ammo caused failures you could walk up and t bag them.

Seriously, how does a company set out to make some thing worse than wolf? It had to take some effort to be this horrible.