Oh, Wise Ones, A little help please.

[Terrill]

I have two problems and could use some help.

First, I was at my range yesterday trying out two different .300 Fireball AR uppers with mixed results.
One was a review rifle and it would break into the golden MOA barrier every now and then but only with loads well below max.
The other belonged to a friend and in every five shot string it would throw one round 2 to 3 inches away from the group. It might be the first shot one time and the third or fourth the next time. There wasn't any pattern. All loads were from the Sierra manual using 125 grain Sierra bullets with either H110 or 296. Any ideas?

The second item I could use some help with is putting together a combination for a new barrel. I want to put together an AR in .300 Fireball to obtain the best results using only 125 to 150 grain bullets at supersonic speed. Most barrels I have seen are in 1-8 twist, would I be better off with a 1-10 or 1-12 for this upper? Would a carbine gas setup work better than the pistol? This will be a single purpose rifle for accuracy and speed.

[Alleycat]

What about this?????

[Terrill]

Honest answer! I'm cheap!
With the Whisper/Fireballl I can use standard magazines, bolt, and .223 brass.
I'm just wanting a handy little "walk around" rifle for my woods. Basically a 150 yard rifle capable of good accuracy. A good handgun use to be ideal but my old eyes just want shoot the way they once did. Coyotes are starting to be a problem (.223 would handle them) but I want to be able to take a Whitetail every now and then. A modern version of the 30-30 lever action.

[Colohunter]

You may search on this site and Arfcom for 7.62x40. I believe a member of this forum had developed a round that was very similar to the Whisper, but with a slightly longer case. When loaded with 125gr bullets it still had the same overall length, but allowed more powder to be used to get slightly higher velocities from the lighter bullets.

[Terrill]

I read everything posted on the 7.62x40 and thought that was the perfect solution. However all of my attempts to find out more information went unanswered. That is what got me looking at the .300 Whisper.
Even as cheap as I am, I've decided to order a custom barrel set up just for the lighter bullets. By the end of the month I should be trying it out.

[Titleiiredneck]

Have you thought about a 762x39 upper or bolt gun? With handloads it can be sub moa. Cheap ammo around also, just food for thought!