Can I improved my 6MM remington

[Plumsask]

Seating the bullets out further will not increase capacity enough to give you a significant increase in velocity. If you throat to allow the bullet with the longest bearing surface to be seated just ahead of the neck/shoulder juncture, the rifle will still be usable with lighter bullets, should you wish to use them. Using an 8 twist barrel will allow you to stabilize most any 6mm bullet, at any reasonable speed.
Chambering to the 6mmAI won't do a heck of a lot either, as far as velocity is concerned; maybe 50 fps or so. WH

I'd have to kindly disagree on the 50FPS, from my experience with three different 6mm Rems and two 6 AI....I've seen about 9% case volume increase and in about 150- FPS increase. Some say the 40 shoulder is also better for the life of the throat..... cant confirm or deny this.

 

[ben lurkin]

I'd have to kindly disagree on the 50FPS, from my experience with three different 6mm Rems and two 6 AI....I've seen about 9% case volume increase and in about 150- FPS increase. Some say the 40 shoulder is also better for the life of the throat..... cant confirm or deny this.

That’s been my experience with the 6 AI too. Can’t comment on throat life yet. Sample size of one and it’s not shot out yet.

 

[David Milisock]

Ok my concept of customizing the throat does not increase case capacity but by allowing the heavier 103/108 ELD bullets to be seated to a similar depth into the case as my 75 grain VMAX. This allows me to recover .235" of case capacity normally lost with seating heavier projectiles, I'm guessing that's more than than enough to experiment with burn rates increasing velocityfor the +103 grains ELD.

I'm researching the 6MM Remington AI and cannot find any load data that impresses me. SAAMI has the 6MM Remington as a 65,000 PSI cartridge. Most magnum cartridges are not rated for that pressure but are called magnums but the 6MM Remington is not.

My listed loads are for a rifle I bought myself as a reward for quitting a job where the owner was an asshole nearly 4 decades ago. I spent 2 years working my varmint load, the Speer and Hornady spire point loads took over a year each. My research shows the AI version only gets about 3 to 4 grains more capacity, not enough to put up with a wildcat for me.

 

[Will Henry]

With a 9% increase in case capacity, you will see about a 2% increase in velocity. This assumes you are loading to the same pressures, with the same components, in the same barrel. The big gains reported by AI advocates are invariably produced by higher pressures. A favorite tact is to compare the AI version, loaded to the nuts, to an anemic factory loading. This isn't comparing apples to oranges; it's comparing lions to kittens.
In theory, one will see about the same improvement with a 6 Rem AI as with a 257 Roberts AI, and this is indeed the case. The thing is, the Roberts does not really yield the results claimed for it, for the reasons mentioned above. Load it hot, and the 257 Roberts performs a lot like it's AI variant.
The claim for reduced throat erosion seems intuitive and I accept it as being possible. Whether or not it makes enough difference to be significant, I can't say. I just have not seen sufficient data to prove it one way or the other.
When it comes to increasing case capacity, the only way it does much good is when the capacity of the cartridge is a limiting factor in achieving max pressure with a given powder. If, with the maximum load, you still have capacity to spare, you will gain little by increasing the capacity. If you are using a compressed load, and pressures are still low, you will benefit by making more room for more of that powder. In theory, a slower powder which achieves the same peak pressure will produce a higher velocity, but this gain is not always as substantial as one might hope. WH