Idaho Elk Hunter

How much free bore should a Remington 700 have? It is chambered in 7mm Ultra. I cant get the bullet close to the lands.

mossy33oak

if the 7 Ultra is the same as the 300 ultra, you will not be able to get the bullet close to the lands.........you just basically seat your bullet so that it fits in your magazine and be done with it. Make sure you can fill your magazine and they cycle properly. example, my magazine in my 300 rum is 3.62" so I seat my bullets to 3.59 col.

Idaho Elk Hunter

So I guess this means rebarreling the rifle? I want to be able to seat the bulet close. Maybe have a reamer made to make it less. I have 3 7mm Ultras and 2 300 Ultras and this is the only one I am having trouble with. The other I can seat the bullet to where you cant close the bolts and the ammo will still cycle through the magazine

mossy33oak

news to me.......if you can touch the lands, are you still keeping enough bullet in the neck?

Idaho Elk Hunter

yes, but with the one Im haveing the problem with I can seat it out to where there is no way it wi fit the mag and still cant touch the lands.

bigcountry

I went on this mission when the 300RUM's came out, I went out to gun stores with my stoney point and a few different bullets. Now, in most it appeared the 3.65" was too tight in the mag. so I would back them down to 3.62" max COL.

Shortest chamber I found, was with a 200gr swift a-frame and that was loading to 3.75". Most hovered around 3.82". Thats almost .2" of freebore. Not near like a weatherby but alot of freebore.

I know a guy who had a custom 300RUM built and he built it so he could touch the rifling and still put it in a 3.6" mag. He couldn't use any loading data whatsoever that was out there. And never did really achieve any groundbreaking velocity. So the actual freebore is needed to achieve some velocity. He couldn't even shoot factory ammo. So think twice before messing around with that freebore.

I have three RUM's and none could you get that close to the rifling and still fit in mag. One was a custom built one with a krieger barrel and done with a clymer reamer.

I highly suggest to not put so much emphasis on touching the rifling if its a hunting rifle. It will cause more headaches than anything. If have the need to be .002" from the rifling for target, I suggest the heaviest bullet you can find. I tried it with 200gr matchkings and it didn't do anything groundbreaking.

stubblejumper

I load my 300ultra ammunition to 3.670" and they work well in magazine.At that length the bullet is .050" from the rifling in one rifle and .120" in the other.

bigcountry

Stubble which one do you see the best velocity performance and which one do you see the best accuracy performance or are they one in the same? Just curious.

stubblejumper

The rifle where the bullets are seated at .050" produces 3380fps with 93gr of r-95 while the other rifle produces 3360fps with 88gr of a different batch of r-25.Accuracy with both averages 5/8".The bullet in both cases is the 180gr tsx.

bigcountry

I would love to know if its cause a different batch or the throat or tighter rifling.

I have seen different batches of RL25 react totally different but nothing as crazy as 5gr. I made up one accurate 180grTSX load in my old 300RUM with one batch at 89gr of RL25, and with a new one, never could get that accuracy out of it again. So I tried some left over ammo from the other batch and sure enough it was more accurate. Never did bother with working the load back up again with new batch. If I ever use it again, I plan to try to buy an 8lb container. But doubt it after those results.