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Barrel is 10.5" with a 1:7 twist. What grain would stabilize best from 50-200yds?

1:7 likes the heavier bullets like 62grn-72grn.

I was afraid of that, I have 2k rounds of 55 grain.

Not like its going to not go bang or not hit the target...just not AS accurate. Aimsurplus has some 62grn PMC for less than $300 a case right now. I'm sure the55grn won't be hard to get rid of though.

rm9792 wrote:I was afraid of that, I have 2k rounds of 55 grain.

What kind? I may be interested if you want to sell it at some point after the end of the year.

Mostly pmc, some american eagle. I have a 16" ar as well as the shorty so i guess i can use it in that one. Will let you know first if i decide to sell it. I sent my scar barrel off to get cut down to 10.5" so i guess i will get some heavier ammo for it.

rm9792 wrote:Mostly pmc, some american eagle. I have a 16" ar as well as the shorty so i guess i can use it in that one. Will let you know first if i decide to sell it. I sent my scar barrel off to get cut down to 10.5" so i guess i will get some heavier ammo for it.

Yeah if you can afford a SCAR you can afford another case of ammo

Sold 3 other rifles to pay for it. It is a heck of shooter though.

rm9792 wrote:Sold 3 other rifles to pay for it. It is a heck of shooter though.

I hear ya...I'm just enviously busting your chops.

I fIgured that. The scar is expensive but i couldnt resist. I got it with 5 pmags for 2k. I try to make my gun habit self paying. Want something new then i gotta trade or sell. I have a weakness for 1911's and AR types. (i hear a bushmaster ACR calling in the distance, must resist.....)

rm9792 wrote:I fIgured that. The scar is expensive but i couldnt resist. I got it with 5 pmags for 2k. I try to make my gun habit self paying. Want something new then i gotta trade or sell. I have a weakness for 1911's and AR types. (i hear a bushmaster ACR calling in the distance, must resist.....)

At least resist until the recall is performed so you don't have an accidental class 3 item.

RECIT wrote:1:7 likes the heavier bullets like 62grn-72grn.

I've always understood the "weight / twist" relationship as such:
As your bullet gets heavier (thus longer), you have to spin it faster to stabilize it. Therefore, the heavier bullets perform better in the 1:7 barrels.

But I didn't think you lost anything by exceeding the twist rate necessary to stabilize the bullet (assuming you're not disintegrating it). I think he'd be fine using 55 grain bullets in a 1:7 barrel. Surely "overspinning" is not as critical to accuracy as "underspinning."

Let me know if I'm missing something....and I'm not trying to be a know-it-all; just don't want anybody to take a bath trading away 2k rounds of suitable ammo.

PQC.

I think overspinning might induce spin drift a lot faster?

PuntoQuatroCinco wrote:

RECIT wrote:1:7 likes the heavier bullets like 62grn-72grn.

I've always understood the "weight / twist" relationship as such:
As your bullet gets heavier (thus longer), you have to spin it faster to stabilize it. Therefore, the heavier bullets perform better in the 1:7 barrels.

But I didn't think you lost anything by exceeding the twist rate necessary to stabilize the bullet (assuming you're not disintegrating it). I think he'd be fine using 55 grain bullets in a 1:7 barrel. Surely "overspinning" is not as critical to accuracy as "underspinning."

Let me know if I'm missing something....and I'm not trying to be a know-it-all; just don't want anybody to take a bath trading away 2k rounds of suitable ammo.

PQC.

You had it right in the term of stabilization. Too fast or too slow is still unstable. Just like a football, you can throw it spinning slow or fast and it can still be unstable. When you release it just right and you get that really tight spiral is what the gun does every shot. In this experiment the barrel is the control and the ammo is the variable. Opposite in the football reference. Football being the control and the human arm/weather being the variable.