Will they ever be accurate???

[Totch94]

I have a new 7mm RUM and have only shot factory Remington Ultra Core-loc 140 gr ammo out of it as of yet. It is a very impressive shooter so far (1/2-3/4 inch with this factory load) Now that hunting season is over I thought I'd start a little load development with it. I started this evening by checking the chamber length...WOW... it is so long that I'll never get anywhere close to the lands. I'm trying to load some Barnes TSX 140's up for it and I have always heard that this bullet needs to be right on the lands. Well, it ain't going to happen here! Just wonder what kind of results I can expect with a TON of jump to the lands with this bullet. Thanks for the input.

Totch

 

[James Jones]

I have seen alot of very accurate Weatherby rifles and all the factory Wby's come with miles of freebore , thats the reason behind them getting the speed they do.

If you use a longer bullet like a 160gr Accubond , or 162 A-max you may be able to seat the bullets out close to or in the lands. Generaly when you seat a bullet out that far and it is in the lands you will not be able to get tom high in the sppeds that some others get asit'll cause a bit more of a pressure spike sooner , but they will likely be more accurate.

Now for your gun , if the throat is nice and strait and you load strait ammo then it should shoot fine having that much free bore and you may find that you can get more speed out of it than listed in the books.

If it were me I'd shoot the longer bullets a little bit slower and take advantage of all that powder.

 

[kraky]

What you have is totally common with a factory rifle of that caliber. Those factory rounds are no where near the lands yet here is a bullet (and not a bullet known for stellar accuracy) that is giving you .5-.75" groups!!
Instead of being worried if you have a shooter.....you should probably be ready to turn down some offers from people that want to buy your gun!!
No...tsx's don't need to be next to the rifling to shoot.....neither do most hunting bullets. There's no reason you shouldn't get the same accuracy out of some tsx's. Stock up on some popular powders for your cartridge....try some different seating depths with the tsx's. I think you're gonna be smiling all the way home from the range!

 

[Varmint Hunter]

I have a new 7mm RUM and have only shot factory Remington Ultra Core-loc 140 gr ammo out of it as of yet. It is a very impressive shooter so far (1/2-3/4 inch with this factory load) Now that hunting season is over I thought I'd start a little load development with it. I started this evening by checking the chamber length...WOW... it is so long that I'll never get anywhere close to the lands. I'm trying to load some Barnes TSX 140's up for it and I have always heard that this bullet needs to be right on the lands. Well, it ain't going to happen here! Just wonder what kind of results I can expect with a TON of jump to the lands with this bullet. Thanks for the input.

Totch

Actually Barnes will tell you the opposite is true with any of their X bullets. Barnes recommends starting with their bullets .050" OFF the rifling and working from there. I have found good accuracy with TSX bullets as much as .150" off. No - that's not a typo, I'm talking about more than 1/10th of an inch. Barnes X bullets are funny creatures but most often they prefer a jump to the rifling for best accuracy.

One thing I might add: Barnes bullets shoot the WORST when there is any other gilding metal jacket material in the bore. If you think the bore is squeeky clean then run a few patches of an aggressive copper remover (CR-10 or similar) down the bore and wait the maximum time recommended on the bottle. If the patches show any blue/green at all, I'd try cleaning a little more before experimenting with these (expensive) bullets.

 

[MagMan]

+1 to what VH said. I have 2 300 RUMs I'm loading for both of which are TSX's @ least .1 off the lands and they both shoot well.

I would not hesitate to try the 160 Ab's in your 7mm RUM teamed up with H1000 (first choice) or Retumbo they should shoot well even way off the lands.

 

[steve4102]

Barnes did a test involving OAL, Pressure and Accuracy. What they found was that in many cases there is more than one OAL sweet spot. One rather long and another rather short. Here is the article.

Barnes Bullets » September 2007 Barnes Bullet-n