I am starting some loads for my Bushmaster and have yet to fully grasp the stabilization issue. I have loaded your basic 55gr softpoints and have had relative sucess with them. I use Varget right now but that might change depending on if I change my bullet.

I completely understand that it depends on the rifle, but What bullets will a 1:9" twist stabilize out of a 20" barrel?

I have used 40 grain V-max to 75 grain A-max bullets. Sierra makes 77 and 80 grain but they say you need 1-8. For long range shooting the 75 A-max have a really high B.C. and shoot well out of all my 1-9 AR's.

all shot in 1-9 AR's.


Hope this helps some

Jason

That is what I thought. I have also used 40 grain V-max with no ill affect on bullet performance.

I think I will still use my 55gr soft points because they are cheap and work perfect for plinking and blasting coyotes.

quote:

Originally posted by MThuntr:
That is what I thought. I have also used 40 grain V-max with no ill affect on bullet performance.

I think I will still use my 55gr soft points because they are cheap and work perfect for plinking and blasting coyotes.

The 1:9 twist is an "iffy" twist for the 75 Hornady bullet, according to local hi-power competitors. Some 1:9 twist barrels stabilize it just fine, others seemingly not at all. Must be right on the cusp.

If I planned on shooting 75 or 80 gr. .224 bullets, I'd go with a 1:8 twist, just to be on the safe side when ordering a barrel or rifle. For 90 grain bullets, I'd use a 1:6.5-----

Is there a direct link between bullet weight and the twist of the barrel? The way it looks if you want to shoot a heavier bullet you should get a faster twist barrel.

quote:

Originally posted by MThuntr:
Is there a direct link between bullet weight and the twist of the barrel? The way it looks if you want to shoot a heavier bullet you should get a faster twist barrel.

There is a direct link between twist rate and LENGTH of the bullet. For the most part, as a bullet of a given diameter gets heavier, it is also longer, but that is not always true.

Anyway, the longer a bullet is, within the same calibre, the faster the twist required to fully stabilize it.

quote:

Originally posted by Alberta Canuck:
There is a direct link between twist rate and LENGTH of the bullet. For the most part, as a bullet of a given diameter gets heavier, it is also longer, but that is not always true.

With the all-copper Barnes X and Triple X being prime examples.

A .308 165 grain Barnes X will be significantly longer than a lead cored bullet of the same caliber and weight, since there needs to be more copper to make up for its density deficiency when compared to lead.

quote:

Originally posted by Alberta Canuck:

quote:

Originally posted by MThuntr:
That is what I thought. I have also used 40 grain V-max with no ill affect on bullet performance.

I think I will still use my 55gr soft points because they are cheap and work perfect for plinking and blasting coyotes.

The 1:9 twist is an "iffy" twist for the 75 Hornady bullet, according to local hi-power competitors. Some 1:9 twist barrels stabilize it just fine, others seemingly not at all. Must be right on the cusp.

If I planned on shooting 75 or 80 gr. .224 bullets, I'd go with a 1:8 twist, just to be on the safe side when ordering a barrel or rifle. For 90 grain bullets, I'd use a 1:6.5-----

Pretty much right on.

If a 1/9 is made on the fast side of nominal (such as when measured it will be 1/9 or 1/8.75), Hornady 75s will spine fine. If it's made a little slow (like a 1/9.25 or 1/9.5) you might not get them to work.

To be safe, go to 70 gr with 1/9, up to 80 gr with 1/8, and up to 90 gr with 1/6.5.

HAve a RRA 20 " varmint barrel in a 1:9 twist that is terrific with the 69 grain Sierras.
The 75 gr. is iffy, I guess I am "on the Cusp" as certain brands of 75 + grains stabilize and others don't, so I limit myself to the 69 which gives excellent performance and groupings

I'm with Gab. I've shot I forget how many pounds of 69gr Sierra's (bought at the factory by the pound) out of 1 in 9 twist barrels. Typically the 77's and 80's are going sideways at 50yds.
Varget is an excellent powder in 223. In a cheaper powder I've had great luck with 24.3grs of AA-2230 and 69gr Sierra's.
The lighter 55gr bullets usually shoot fine also but I wouldn't try anything heavier than 69grs in a 1 in 9 as it starts getting marginal................DJ

As others said, the 75 might stabilize, it does in my savage 1/9 twist with 24 in barrel. The 69 sierras are a good bet. You might want to also check the 68gr Hornady HPBT, I think it has a higher BC than the sierras. I have no experience with them, but you may want to take a look anyway.

quote:

Originally posted by Justin B:
As others said, the 75 might stabilize, it does in my savage 1/9 twist with 24 in barrel. The 69 sierras are a good bet. You might want to also check the 68gr Hornady HPBT, I think it has a higher BC than the sierras. I have no experience with them, but you may want to take a look anyway.

Yes, the 68 Hornadys might work...might not, too. The reason I say that is that bullet shape has a lot to do with its resulting length.

VLD bullets (Very Low Drag) for instance, have such long points for their weight that they will not always stabilize in the same twist as other bullets of the same weight.

Having a boat-tail also increases length for the weight.

That's why Walt Berger introduced LD (Low Drag) bullets in addition to his VLD bullets. The LDs have basically the same pointy nose as VLDs but a flat base, which makes them a little bit shorter than the boat-tailed VLD bullets of the same weight, and therefore easier to stabilize in a slightly less rapid twist.

68 grain Hornadays should be no problem.
69 grain Sierras should be ok too, but you will have to check them to be sure.

Just don't use Hornady's SPSX bullets with a one in 9 twist...they are too fragile....will disintergrate right out of the barrel....

I have a RRA AR, in a 1 in 9 twist. It loves 55 gr VMAX, and is ok with 60 gr. My Savage 12 prefers 60gr VMAX.

I would try to stay under 70gr, as a 1-9 twist is right on the edge of stable for a 75 gr pill.

OK then, what weight bullets should my 223WSSN 21" 1-10 twist shoot well?