This has been one confusing decision for me to make, maybe you can help....I got a good news call last night from my cousin who lives in the Adirondacks, his buddy owns over 600 acres and will allow us to shoot on his land, there are many safe areas to shoot varmint and target!!!!
I have been wrestling with building something off a Savage Action and have seen a lot of good posts on the 6.5-06. My question is this: Is there any advantage to an A.I. Version?
What would be a good length barrel (shot from a bench, weight not a major issue)? Shots could exceed 1000 yards by the power line cut-outs.
I am looking to get this right the first time, and you guys have been a great help in the past!
"A tie is as good as a loss, and no one remembers second place."
Cannot give factual stats on 6.5/06 as I do not have one but they are commonly listed in reloading manuals. I do have a 6.5/06 AI. It has a 28" barrel and with 140 gr bullets I can easily get 3000-3050 fps depending on exact bullet and powder. It is a very accurate cartridge with good velocity for 142-147 gr bullets if you are familiar with reloading and fireforming this type cartridge.
An AI version (35 or 40 degree shoulder) requires you to fireform brass before neck turning so that is another step you have to go through. Either Lapua 30-06 or 270 neck down then fireform with cream of wheat and very fast pistol powder normally topped off with tissue paper, wax etc. Requires you to leave a partial shoulder (not size neck all way down) on bottom of neck to crush fit case into chamber for fireforming.
Mine was built before the 6.5-284 had decent brass and I would recommend that you really look at 6.5-284 with 28-30" barrel if you are not comfortable doing fireforming etc. Just neck turn load and shoot, no fireforming etc and can get virtually same results especially if you use a tapered 30". Difference in same length barrels is probably 50-100 fps less for 6.5-285 versus 6.5-06 ack improved.
I shoot a 6.5/284 with 140g AMAX and 142g SMK. The barrel is a 28 in 1.25 heavy varmint straight taper. I would recommend using the 140g Amax for varmints. I shot a Prairie Dog last summer at 1040 Yards with this gun and had a string of 5 Dogs in a row from 500 yards to 650 yards
If you think something is not possible move out of the way so the ones that are doing it can
An improved version of just about any cartridge is going to give you the potential of higher vel, all else being equal. A bigger "boiler room" for more powder - higher vel. I say potential because accuracy may not be there at the higher vel. A risk with any cartridge.
The question is should I bother. The 6.5-06 is a great case and works very well. The AI might give better case life because of the sharper shoulder. It may give higher vel and certainly will give the same vel at lower pressures. I like the look of improved case so would lean that way.
In fact, for me, the 260 AI with a relocated shoulder would be just about perfect. Use match 308 brass and performance similar to the 6.5-284/6.5-06 without the throat erosion. Get a tight neck if you can neck turn. Will help with accuracy.
I would look at a non tapered barrel 28" to 30" long. Get it as heavy as possible so recoil is nil. A good bench stock and enjoy.
The 140 class of bullets are great and the Amax and MK are both top choices. Get a 1 in 8 twist.
I've seen enough of both cases used in competition to say that both have the same potential for accuracy in my book. I wouldn't give the accuracy nod to one over the other. The AI will give you more horsepower if you plan on any LR deer hunting. But for varmints it's really not needed. The extra velocity will help a little with wind drift but it really isn't the big of a difference if you look at a ballistics program. If you as the shooter miss a reversal in the wind, the AI won't shoot through over the std case. You still have to steer it correctly to begin with.
I would have to say that case stretch with the AI case is an advantage over the std case as mentioned above. But the flip side of that coin is in fire-forming cases. Depending on the methods you use it's more time and wear/tear on your barrel. Now when I fire-form AI cases I use the cornmeal method w/ a small amount of shotgun powder and a wad of toilet paper to hold in in the case against the primer. This blows out 98+% of the case. I've fired many small groups on the second firing after using this method and your headspacing is good. But if the shoulder moves forward I prefer to use the 90% load of your regular load, w/ the bullet seated long, and a lubed case to fire-form.
28-30" barrel length is a very good for this case capacity. You could go longer, but if this is a carry gun 28-30 will do what you want with very good velocity and decent portability.
So if you find a good local smith that has one of those two reamers then just use the one he has and don't look back. If you have a choice or your going to buy the reamers outright, that's part of the fun of building a new rifle is deciding the caliber.
Note: I've got both 8" twist and 9" twist 6.5 barrels currently and have fired enough 8.5" twist 6.5 barrels that I wouldn't recommend the 8" twist for varmint bullets. Especially the 140gr A-Max. You will have to slow them down to get accuracy out of the 8" twist. I've compared notes with my 8" twist barrel a fellow competitor who used a 8" twist also and our results were the same with the 140gr Amaxs. Now in a 9" twist... the 140gr A-Maxs shoot! Period.... end of story.
I wonder if you would expand on a few things a little more concerning your fireforming techniques mentioned here?
Now when I fire-form AI cases I use the cornmeal method w/ a small amount of shotgun powder and a wad of toilet paper to hold in in the case against the primer. This blows out 98+% of the case. I've fired many small groups on the second firing after using this method and your headspacing is good.
What shotgun powder works well, do you use? I don't know what the guys use to load for them shotguns anyway.
How do you know how much cornmeal to use?
I imagine enough TP wadded up to hol it all in while firing?
When you say it blows out 98% of the case, does this mean the shoulder isn't all the way to shape but headspace is good or what two percent is left to be blown out more?
But if the shoulder moves forward I prefer to use the 90% load of your regular load, w/ the bullet seated long, and a lubed case to fire-form.
Sorry, but what do you mean when you say "if the shoulder moves forward"? I probably misunderstand you... Do you mean moving from the firing pin impact because there's not enough resistance from the semi-shoulder to headspace on?
Lubed case? I assume this is safe with a reduced load... as you are indeed doing it.
Do you lube each case before firing or just every few loads... does the lube build up in the chamber after a few and is not needed after?
I assume you use a very thin amount of lube too?
I'm taking notes and I can't think of a better source so... I am probably looking at doing this very soon and you sound like you have this down to a science.
Appreciate the lesson if you have time.