Scar 20S picky eater??

[schmi015]

So I took my scar 20 in 6.5cm out on it's second range trip to do some plinking and just see what's up. My first range trip with it was a little frustrating. So I'm guessing it may be a picky eater, it has the HP bolt and firing pin. Hornady 140 ELD-m's and 140 Eld-x rand and shot just fine. Out of a 20 inch barrel, I had a 5 shot avg of 2617fps sd11 and a spread of 30 with ELD-m's and eld-x's 2630fps 13.6sd and spread of 36. Those all ran and cycled fine.

I had a box of berger 130 grain were the rifle would consistently fail to load the next round effectively turning it into a single shot rifle. velocity was 2789 sd 9.5 and spread of 25. Just curious if anyone else has tried the berger ammo in their scar and what their results were like?

 

[nn8734]

So I took my scar 20 in 6.5cm out on it's second range trip to do some plinking and just see what's up. My first range trip with it was a little frustrating. So I'm guessing it may be a picky eater, it has the HP bolt and firing pin. Hornady 140 ELD-m's and 140 Eld-x rand and shot just fine. Out of a 20 inch barrel, I had a 5 shot avg of 2617fps sd11 and a spread of 30 with ELD-m's and eld-x's 2630fps 13.6sd and spread of 36. Those all ran and cycled fine.

I had a box of berger 130 grain were the rifle would consistently fail to load the next round effectively turning it into a single shot rifle. velocity was 2789 sd 9.5 and spread of 25. Just curious if anyone else has tried the berger ammo in their scar and what their results were like?

How did the groups look (size, mean error radius) for each type/brand of ammo you tried?

SD/ES numbers are largely irrelevant if you only tracked 5 shots for each ammo type. Even then, lets say they're representstive of the population - those numbers are fine for factory ammo.

 

[oldrifleman]

Were the cartridge length on the burgers and Hornady the same? And was the failure on mag extraction or feeding to chamber?

 

[schmi015]

How did the groups look (size, mean error radius) for each type/brand of ammo you tried?

SD/ES numbers are largely irrelevant if you only tracked 5 shots for each ammo type. Even then, lets say they're representstive of the population - those numbers are fine for factory ammo.

I was more just testing for function, I was shooting a piece of steel at 200 yds, groups were tight but I didn't measure. My first range trip with the rifle gave similar results with Berger, i was hoping by running some more Hornady through it, it would break it in, but the Berger stuff failed to load the next round, was consistently ejecting though not sure what the issue is.

 

[schmi015]

Were the cartridge length on the burgers and Hornady the same? And was the failure on mag extraction or feeding to chamber?

I didn't even measure CL, its not feeding the bergers to the chamber.

 

[Huskydriver]

Uh obvious question....is the gas all the way open?

 

[schmi015]

Uh obvious question....is the gas all the open?

It's on the non-suppressor setting. Cycles just fine with the hornady stuff. I'm running it with the factory muzzle brake.

 

[Huskydriver]

So are you getting a ftf or it's ejecting but not getting enough gas to pick up the next round

 

[schmi015]

So are you getting a ftf or it's ejecting but not getting enough gas to pick up the next round

it's ejecting but not getting enough gas to pick up the next round

 

[Huskydriver]

And you are sure it's on the reg setting 12oclock? If it is I got nothing on how to fix that

 

[schmi015]

And you are sure it's on the reg setting 12oclock? If it is I got nothing on how to fix that

Yep, its at the 12 o clock position. I've heard the berger stuff runs hot, i get that the bullet weight is 10 grains less but it's pushing it out 166fps faster than the hornady, it is possible the carrier/bolt is just shooting over it before it has the chance to strip the next case?

 

[Huskydriver]

Yep, its at the 12 o clock position. I've heard the berger stuff runs hot, i get that the bullet weight is 10 grains less but it's pushing it out 166fps faster than the hornady, it is possible the carrier/bolt is just shooting over it before it has the chance to strip the next case?

I mean that's pretty wild if it is... Try putting it on supressed... In theory if your assumption is right, it should pick it up on the smaller amount of gas

 

[dms416]

Yep, its at the 12 o clock position. I've heard the berger stuff runs hot, i get that the bullet weight is 10 grains less but it's pushing it out 166fps faster than the hornady, it is possible the carrier/bolt is just shooting over it before it has the chance to strip the next case?

Old HK416 10.4's had this problem when running suppressed on 5.56 pressure ammo. They had to add a bleed-off valve to the gas block similar to the 14.5" and longer barrel variants. The gun was running faster than GI mag springs. Some found that mags with stronger springs helped this issue.