A friend of mine and i both have TC barreles in 7/30 waters, he wanted more vel. out of his and sent it off to be rechambered to a 7GNR, when he got it back we fireformed the brass with the loads we have always used, 35 grains of AA2460, gave us about 2600 in the 14 inch barrel.
After fireforming the brass we started working up a load, 36 grains of AA2460 was max for both guns before, we ended up at 40 grains and only gained 85 FPS out of 4 grains, just starting to show pressure so we stopped there, accuracy is pretty good, as good as it was before rechambering, but was thinking we would gain more velocity, can you advise us on why were not getting anymore vel. should we change powders, were useing the 120 grain hornady ssp bullets, thanks for any help, Bubba.

Maybe you're just blowing extra powder out the barrel! roger

Isn't the general rule of thumb about 4 to 1 with 4% capacity increase only giving 1% velocity increase
a 4 gn capacity increase on a 36gn case is 11% so there will only be aprox 2.75% velocity increase and as the original velocity wasn't given then 85fps may or may not come within that rule of thumb, however unlikely it is for the 7/30 Waters, if you were getting 3100fps then 2.75% is the 85fps increase.

Original vel. was posted, it was 2600, im not to impressed, with the rechamber price and the custom dies it was not worth the effort i believe not for 85 FPS, may try a faster burning powder and see what happens, will see, thanks.

Bubba,

Have you given Gary Reeder a call and see what powder he recommends??

I would say a powder change amybe in order to get the most out of it.

BD

quote:

Isn't the general rule of thumb about 4 to 1 with 4% capacity increase only giving 1% velocity increase

quote:

Originally posted by bartsche:
Maybe you're just blowing extra powder out the barrel! roger

Ditto.

Rule of thumb:
More case volume needs a faster powder OR a longer barrel. I prefer the longer barrel route as faster powders make you reach max pressures to quickly.

Gary Reeder includes a reloading chart with his rechamber job but everything we tried didnt give us the vel. we were getting with AA2460.
I talked with another 7X30 waters fan on friday and he told me to switch to WW748, i had a chance to work up some loads yesterday and it is giving us very good vel, more like what we were looking for, i cant wait to try it in my unaltered 7X30 barrel, he said it was his go to powder for the 7X30 and from further research on the net others say the same thing, thanks for the input, Bubba.

with a similar wildcat of mine (7x41) and 110 to 130 grain bullets and a 16" barrel the rifle was performing really good with 8208 and 2200. Just a thought. The powder you are using now seems just a tad slow burning for cal. capacity, barrel length combo. roger

quote:

bartsche

Bartache

Im not dont have eather of those powders and have never used them before, the faster powders reach peak pressures before i get any vel. improvement, is the cartridge you talk of based on the same size of a 7X30 improved, thanks again for the input, Bubba.

My 7 X 41 will hold 3 less grains of h4895 than the 30-30. roger

Peak pressure isnt related to velocity. Area under the curve or pressure over time. Fact is that every reloading book shows this if you know how to read them.

You get 25% increase in Vel for the same pressure curve with the same bullet for the charge in capacity.

36 to 40 isnt really relevant but here goes

10% increase in powder burnt would be 2.5% increase in Vel. Or 65 fps of 2600