New Grendel, strange performance

[ugadeer]

I just got this AA piston grendel with the Vltor VIS2 upper (1-7.5 cut rifled satern barrel), AA lower, AA precision trigger, added a Magpul UBR and leupy mk 4 3.5-10 M3 in a burris pepr mount.....took it to the range for break in with some factory ammo that came with it

90 gr tnt shot sub moa 5 shot groups at 100
129 gr hornady sst shot sub moa at 100, more like .7
130 gr swift scirocco shot like absolute shit.....4-5" at 100

I shot all three loads the same, same cooling, same rests/mags/etc.....i'm baffled at why the scirocco's wouldn't perform bc that is the bullet that i wanted to load for this rifle as i'll be shooting deer for crop damage mostly (waiting on my form 4 for a gemtech sandstorm, its been 3 months)....

any ideas as to why the swift ammo sucked so bad? thanks

 

[Ando]

Re: New Grendel, strange performance

The scirocco is bonded that makes for a bullet that is not very uniform in internal construction. That combined with the fast twist hurts accuracy.
The jacket is also pretty thick. The diameter maybe on the small side for your bore.
Not all bullets work in all barrels, and I have seen poor performance from the Scirocco before, however, not that bad, and in .30 cal.
Why not just use the SST? It is a good Bullet.

 

[ugadeer]

Re: New Grendel, strange performance

i was looking for a littel more controlled expansion so i guess i'll see what i can find in an accubond.....i'm only shooting the factory AA ammo b/c it came with the rifle and i want brass.....i've had really good performance out of the 180gr scirocco in a 300 WM and the 75 gr in my 223's so i guess maybe i just had high hopes for the grendel offering

 

[FCS]

Re: New Grendel, strange performance

I'd try some hand loads before giving up on the 130 Scirocco. AA2520 would probably be your best bet with that bullet.

120s, IMHO, are about the limit for the 6.5G when limited to AR mag length.

2600 with 120 Nosler BT or 2850 with 100 Nosler BT should work quite well on deer sized game.

100 Barnes TTSX might be worth looking at also.

 

[He Shoot Me]

Re: New Grendel, strange performance

Bummer......

I was reeeeeally hoping to use the scirocco in my 6.5G I hope someone comes along that has figured this out.

-Pat

 

[Casey Simpson]

Re: New Grendel, strange performance

A Grendel is not going so fast that controlling expansion is a problem, but try an Amax.

 

[ugadeer]

Re: New Grendel, strange performance

FCS......i like your thinking with the barnes bullet, the reason i was going for the heaviest bullets was the 7.5 twist but y'all are probably correct about the 100's as the 90 speer tnt's shot pretty damn good

i'm going to gather some bullets and try to load some this weekend and see what they do next week on the range....i'll keep you updated

 

[Ando]

Re: New Grendel, strange performance

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Casey Simpson</div><div class="ubbcode-body">A Grendel is not going so fast that controlling expansion is a problem, but try an Amax. </div></div>
+1
The 130 Scirocco is designed for a much faster cartridge then the Grendel, and too little expansion would be more likely.

The SST really looks like a good match for your use, same with the Ballistic Tip and the Amax.

 

[Ando]

Re: New Grendel, strange performance

Double, I blame the iPhone....

 

[ugadeer]

Re: New Grendel, strange performance

well its certainly hot and humid here as well and everythin i've read on other sites points to blc2 powder and the favored for the heavier bullets in the grendel so i think i'm gonna get some and see if i can work out a load......gun's at the smiths now getting an adapter made for suppressor

i'll try to post when i'm able to test some loads again

 

[Shaun Miller]

Re: New Grendel, strange performance

My 16" like's the AA factory 130 scirocco's .7 in @100 average.

 

[babue]

Re: New Grendel, strange performance

Just another idea. If this is a new rifle that you just started
shooting, did you check that nothing has come loose, like the gas
block. Things seem to come loose on Grendels. That is why AA uses
Loctite on their builds.
Were the Scirocco's the last load you shot and did you try any of the other loads after the Scirocco's to make sure they were still shooting the same. The fouling built up in the barrel from the other loads may not have agreed with the Scirocco's unless you were cleaning constantly during break in. Shooting something else after Nosler's seem to have that problem in my Grendel's, maybe the same case here.
Always something else to look at.

 

[ugadeer]

Re: New Grendel, strange performance

Bruce, good thoughts and thanks, the swifts were the last load that i shot but it was immediately after cleaning so fouling shouldn't be an issue but i did not check the gas block.....i'll give it a try

 

[generalquark]

Re: New Grendel, strange performance

I have not heard much about the Scirocco's. Did you check on the 65grendel forum yet to see if anyone on there has posted about them? I have heard nothing but good about the 123gr lapua scenars, but they are a more expensive round. Good Luck