Does anyone have any experience with this cartridge -- What is a good powder/load to start with? Thanks

Start with middle of the road standard 25-06 loads and work up. There are a lot of variables to account for, so jumping in at the deep end is risky. I think you will find RL22 and powders in that range will work about the best. This is a somewhat overbore cartridge, so the slower powders will probably be your best bet. - Dan

The 25/06 Improved is a death ray on whitetails-have had two of them, the first one was stolen in a break-in at my house-rem 700 action and it shot 100 gr. speers with 58.5 gr of Re22 around 3700 fps with .5 moa accuracy-killed two does with it and they went two feet....to the ground! My second is on a VZ-24 action and it doesnt like Re 22-although it will handle more pressure than the 700. It likes 56.0 gr. of IMR 4350 at around 3500 with 100 grain pills. I havn't experimented too much with the second one though and im sure I will be able to find different loads that do a little better. YOU NEED ONE OF THESE!!!

I have used a 25/06 Ackley Imp with 40 degree shoulder for about 15 years, and for a hunting rifle on medium game here in Australia, I believe it is very close to ideal.

Regarding starting loads with a fireformed case, I believe that the advice of member Dan Belisle is spot on. Start with what are normal or safe pressure loads for a particular powder in the standard case, and work up from there.

However in fireforming the cases, the advice of my gunsmith was to use a near maximum load in the standard case, and make sure the bullet is seated about .020 into the lands. If you use a load that is too mild, you will end up with cases that have round shoulders. I have found that his advice has worked well with the fireforming of all my wildcat cases.

I also agree with his suggestion to start with powders with a burning rate like Reloader 22. I have found that with the 100 grain bullet, powders of similar burning rate, such Hodgdon 4831sc, WMR, Vihtavouri 165, are close to ideal, although I found that IMR 4831 which is a little faster, was also very good.

I also agree with the comments of another member Holmes, about the wide variety of rifles and chambers, which emphasises the need to tailor the loads to suit your rifle.

To emphasise this point, I noticed that another member Frasier Bullington used 58.5 grains of Reloader 22 in one of his rifles to achieve 3,700fps. In my rifle which is Sako L61R sporter with the standard Sako 23.5 inch barrel, I need 62.5 grains to reach maximum pressure and a velocity of about 3,575 fps, and my starting load with this powder of 59 grains gave 3220 fps.

With all my wildcat cartridges, I measure the case capacity prior to fireforming and then again after fireforming to obtain accurate information on the size of the new case, and what the increase in volume is over the parent case.

In my 25/06 Ackley Imp, the Remington new brass in 25/06 had a water capacity of 65.5 grains, and after fireforming the improved case had a water capacity of 71.2, which is an increase of 5.7 grains, which is an 8.7% increase in capacity.

This increase of 8.7% in capacity gave me an increase of 7.9% in velocity with the 100 grain Nosler SPBT. As an example, in the standard case 56.0 grains of IMR 4831, gave 3324fps, and in the same barrel about 400 shots later, after rechambering to the improved case, 60.0 grains of IMR 4831 gave 3,589 fps.

I hope the above info, helps to get you started. Good shooting. Brian

To clarify, My model 700 had a 27" Shilen barrel.
These velocities seemed high to me also with a not so heavy powder charge for the improved cartrige,but at 59.0 grains of Re 22 it was blowing primers out!!

On another note, high charges of re 22 in my VZ-24 showed extreme velocity spreads(80-100 fps)
what are your opinions on using magnum primers
to get consistent powder ignition?