i'm starting the planing for my first custom rifle I will build myself. it'll be rem700 action Shilen 1/8twist 26" #7 in a McMillan Dunlop stock. i'm building this for longrange coyotes and ground hogs.
not much differance in any of the chamberings do any of them stand out for good or bad?

Outlaw,

I would go for either 6mm/06 or 264 Winchester.

Mike

OK I'll add my 2 cents with my first cup of coffee. I have a 6.5-06. Actually it is now an Ack Imp. I've had a 264 Win Mag. the one I shoot the most is basically a 6.5 Gibbs.
There is really no increase in capacity (for the same OAL) between the 06, 280, 270. Yes I know the shoulder is a little forward but, not enough to matter. The Ack Imp will give you some increase over the 06. If you want the most capacity out of an 06 size case consider the 6.5 Gibbs. It is an imp case with the shoulder moved forward at 35deg. I built mine on a 280 case and used a 40deg. It will do anything a 264 will do in a 24" barrel. The 264 will give you an increase over each of these. But, it requires a magnum bolt and in my opinion a longer barrel to use the extra powder. Using my wildcat I move a 140 gr right at 3200 in a 24" barrel. Powder is MRP

which case is the least hassel to form?
which brand of brass? titeneck?

I have always used Norma. I've found that it's inside capacity is a little larger than the other brands with excellent quality. But, if you go 6.5-06 stay away from the 270 or 280. The case most likely will be too long and need to be trimed. the 6.5-270 or 280 are really not standard wildcats. More expensive for dies etc. The Gibbs and AI both need to be fireformed. The most simple. Get 25-06 either Rem or Win. Run it in a 6.5-06 FL die and you are done. If you want real quality brass get 30-06 Lapua. Run it in the die. Depending on your chanber you might need to turn the neck but I doubt it. As someone mentioned there is also the 6.5-284. Brass is available. However some actions need some work to get them to handle the shorter fatter case.

Yep,..I just took 25-06 win brass and ran it through the expander mandrel for 6.5mm, and then loaded bullets into the lands and fireformed with RL19 for my 6.5-06imp. The gun is doing .5moa while fireforming with 140gr SST's. My barrel is a 1:8 PacNor. I have 2 AI chamberings,..and will have plenty more in the future. Great brass life,...positive headspacing.

Outlaw:

I have a 6.5-06, built on a Springfield action. I use 270 Win. Remington cases and trim them to 06 lengths. I do this so as not confuse any of my 270 Winchester ammo, in which I use Winchester brass. I don't find it a hassel to form the 6.5 out of any of the 06 family of cases, as long as they are trimmed, if necessary. I would guess, and I not an expert in this matter, that you could successfully size 6.5 X 280 imp brass in a 6.5 X 06 improved die, as the .050 difference in case length may not be a problem.

Jerry
The reason we all build wildcats, is so we have something different to fool around with!

Go with the 6.5 Gibbs. Use some quallity brass such as Lapua or if cost is an issue get some 30-06 Match brass.

I haven't got anything against any of the calibers you are considering but I think I would go with a 6.5/284 for one thing is you already have factory brass or neck down 284 brass. The 6.5/284 is a proven round in the long range game. I plan on using mine for long range PD this year and maybe a antelope hunt if I get drawn. Mine kind of likes the 140/142gr Sierra bulets and most get the best when velocity is around 3000fps. I kind of looked at the 6.5x55AI and acouple of others but settled on what I did and right now glad of it. Well good luck Tom

In the field all of these cartridges will yeild the same performance. The velocity edge of the AI is really hard to realize by most good hunters. You will however be given the privilege of using more powder to do the same job and blowing out those cases. What does a differential of 4 to 5 inches at 375 yds mean in the real world? Since you will be building a rifle for the first time consider the ease of using a reamer with a 17 degree shoulder contrasted to one with a 40 degree shoulder. Feeding may be another problem you'll have to address with the AI depending on your action it's rails and follower.

And this answer is------256 Newton roger

I thought I read some where in here(i think) about a 6.5 WSM.....just a thought, could be another option.

Outlaw Sir:

They are all barrel burners sooooo why not the 6.5/284 a hummer( still a barrel burner) but one can use a shorter action.

Clarence

If barrel burning becomes an issue, theres always the .260 Rem....long barrel life-factory ammo avail-short action-brass everywhere....choices choices choices..