Changing from 7-08 to 7mmBR

[karlrudin]

IN YOUR OPINIONS, I am currently considering converting my 7-08 to 7mmBR in a quest to lighten my recoil but hopefully tighten up my groups. What I would like is y'alls input on how 7BR performs, pitfalls or problems with the cartridge. I have been seeing a LOT of winning scores from the 30BR folks. But since I already have a 7mm bore, I was going to try this rout first. All commments welcome. Currently I'm using WW/2% Tin water dropped. A Lyman 7mm 160g #287641 mould. Aluminum gas checks, glued. Lee Alox cut 20% with mineral spirits. Average velocity, 1500. My groups generally hover between 3/4-1" overall. Thanks y'all.

[joesig]

My two cents owning both calibers in a Featherweight and XP100. If you rechamber, you can get a "better" chamber so that is a benefit. I am a fan of a larger case to allow for slower powder and a more gentle push if I have the option. You may want to consider the load you wish to use to decide case volume. IF you rechamber, will you use necked up Lapua brass to take advantage of the small primer or just chop up 7MM-08 cases?

[RU shooter]

I really don't know much about the 7BR but if your goal is lighten recoil your only gonna get that by either shooting a lighter bullet or shooting the bullet you have now slower . Or get a heavier rifle . By moving to a smaller case with the BR your recoil will be the same if not a little more because your pressures will be higher in the smaller case with a similar load

[runfiverun]

your not gonna gain recoil reduction with a rechamber.
if your looking for accuracy, velocity changes can help, and a powder change can help too.
but a boolit design change and a straight start would trump both of those in an instant.
adding weight to the rifle and reducing the projectiles weight will lower your felt recoil.

anyway the 30 guy's are doing so well because they are re-forming their boolits to match their throat and are getting tight chambers cut so they can match their brass to hold everything straight.
it's a ton easier to get bump dies for a 30 cal rifle.
a guy I know say's they need to change the name from the bench rest cast bullet shooters to the bench rest swage bullet shooters society.

[karlrudin]

More info, load density is what I was thinking about using the 7BR. As it is right now my sweet spot is only using 20g of IMR 4198. Lot of air space left in the case. I have tried several different powder changes and it seems to like this one. From HS-6 to IMR4064. My bore does NOT like the lighter bullets because I have a 130g mold also and the best it will do is about 2". As far as the bullet starting off inline, I use a bore rider which is .001 larger than the grooves and my first driving band is imprinted into the lands also. Thus is should be starting off straight. Along with the fact that my case neck are .003 smaller than the chamber since I turn my necks. I was advised not to make the necks any tighter. This might not be true though, but my thought was on to tight of a chamber to neck clearance thus a bullet release problem. As far as adding more weight to my weapon, this I'm kinda stuck at because I have to stay under 14lbs for shooting in tournaments. And I'm at 13.5lbs. Thanks for the info thus far though. As far as cases go, I have tried Lapua 308 Palma cases with the small primers pockets, but my Remington brass still seems to do better.

[BK7saum]

If a factor chamber and barrel it may not be straight. The chamber may be cut true to the OD of the barrel, but maybe not true and square to the bore itself. A good smith would dial in the bore before reaming the chamber thus ensuring that the chamber is true to the bore. Just because youre doing everything to start the boolit straight, still doesn't mean that it is.

[karlrudin]

I agree 100%. I have seen this problem before. In fact this is a Shilen barrel that was installed. This might take out "most" of the problem of alignment since they are a reputable barrel manufacturer but I haven't had the action trued to the bore. That's getting a bit much out of my budget. I would have to be making money out of shooting to justify some cost like that. Just saying it should be more true than a factory barrel.

[fourarmed]

It is awfully hard to beat a .30 caliber for cast bullets. I have a couple of XPs in 7br, and the one with the newer barrel shot cast pretty well for silhouettes (when I could still lay down, shoot, and jump back up) but it was not as accurate as my pal's .30br. On the other hand, his has a blueprinted, after-market barrel installed and chambered by an experienced benchrest gunsmith.

[karlrudin]

Yeah, well my pockets don't run that deep for having my rifled sent to a shop. So far I've done all the work myself. Not knocking, just ain't in that tax bracket