barrel harmonics

[westernsky]

g'day all
i have a 300RUM which is getting rebarrelled and a new stock fitted. the barrel has a screw on brake which i obviously cant use on the range, i added it so i can practice at home without killing my shoulder!
what im concerned about is once i develop a load at home and test and sight in with the brake fitted, how much of a difference would it make to the POI once its removed.
would it be a good idea to get a tuner made to the same weight to screw on at the range?

[Razer]

I would say yes, for many reasons.
Having shot a hunting weight 300 RUM 'TWICE', which doesn't give me a lot of credibility in discussing this calibre, but, in your other post, I had intended to query why you would want to use such a hard kicker, and from the prone position, for a minimum of 10 consecutive shots, followed by the same minimum 10 shots? I would not like to do so.
If memory serves me correct the case has a 110 grain capacity so you are burning a lot of powder, and barrel life in a range shooting scenario is going to be limited. Sounds like an expensive calibre to run in range competition if you intend to exploit the heavier weight projectiles at the ultimate/optimum velocity.
My thoughts would be to get a more user friendly calibre by changing barrels to a different calibre for the range.
Just an opinion that others would like to comment on.
Ray.

[bruce moulds]

western,
your poi might or might not change.
the other thing that might or might not change is the size of your groups.
even with a replacable tuner, you might need a seperate load, but the seperate tuner might let you tune the same load to be o.k..
whatever load you run with, it will need to have a velocity s.d. of less than 10 f.p.s to be good at long range.
the only advantage of your big case is to deliver more energy at long range.
disadvantages include the fact that you might shoot the barrel out trying to establish a good load, while developing a flinch.
the muzzle brake will cut recoil, but it increases violence directed backward, which your brain will not like.
be aware of your 10 kg weight limit. sometimes a tuner can add too much weight. if this is the case, a lighter scope can help.
keep safe,
bruce moulds.

[westernsky]

thanks for the tips guys
in response to why i chose such a big case is simple, i originally wanted to learn to shoot out to a mile and figured heavy projys and velocity would allow me to do that. maybe i was naive but hey, ive come this far, may as well give it a go!
im aware of barrel life, but unfortunately, or fortunately depending on how you look at it, due to work and family commitments i wont be able to make it to the range every weekend, and unless its a comp, im happy to shoot two targets for the day.
i also have my .243 for shorter ranges. its a tack driver out to 400 so im happy with that! ihave shot 800 with it but im long out of scope adjustment. still never missed though!
happy shooting!

[Norm]

Westernsky,
Don't be put off.
It wont hunt to have an occasional shoot with a RUM.
If your rifle is up near the 10kg limit and has a good recoil pad like a limbsaver then it will be fine to shoot without a brake.
If you like you can also fit a couple of mercury recoil reducers into the stock.
Run a suitable powder charge to give good case life and your barrel will not burn out any faster than some of the hot 7mm cartridges that are being used in F-Open. Work out the powder to bore ratio and they are not that far behind.
My brothers .300RUM is shooting very well with 88gn AR2225 behind the 230gn Berger Hybrid.
Work out the numbers for a .743 BC, Berger Hybrid at 2950 fps.

[westernsky]

cheers norm
so far ive been running 95gn of 2225 with nosler 180 ballistics but ill be changing to probably 200 or 210 sierra matchkings. it would be nice to keep my mv up close to the 3000 mark, but maybe im dreaming!
im not to worried about recoil, it was a very light rifle before and i managed, it was only around the 4 to 5kg mark from factory.
the new trueflite 30" barrel is nearly that on its own!

i still have alot to learn about load development and reloading techniques, case/bullet prep etc. im doing alot of reading!

i was going to run 240 sierras but according to their site they need a minimun 1 in 10 twist. my new barrel is a 1 in 12. hoping i havnt made a mistake there.

[Norm]

The 1 : 12 twist barrel will makes a big difference in limiting your ability to use the higher BC bullets.
Bullets in the 185 to 190gn weight range would be ok but the 210's might not stabilise.

[IanP]

The biggest case I have ever seen shot in F-Open was Paul Janzso's 30cal BooBoo with 180 to 210gr projectiles. The case is based on a RWS 8x68 and is as long as the lapua 338 magnum case.

Picture of long range cases here (scroll down) http://www.freewebs.com/ukbra/riflescartridges.htm

The case capacity is about 70grs or so but it still recoiled pretty hard. Paul is one of the best shooters under heavy recoil guns I know but the BooBoo proved to be too much for him to shoot accurately. Used as a heavy benchrest gun in a suitably heavy stock and a custom rest this could be the ultimate 1000 yard gun. I think the 300Rum would be too much recoil in a 10kg rig to be competitive in F-Open but if you dont give it a go you will never know!

Ian

[westernsky]

after a bit of research of bullet manufacturers i think ive settled for the 200gn sierras. just got to work out a load.
that 30 is a big cartridge but the RUM has more behind it than the 338. i originally looked at the 338 but being a "military" round its hard to get here in WA.
the recoil wih the factory rifle was manageable so with the extra weight im sure it will be fine, or maybe im just a sucker for punishment!!
guess ill find out if i can make decent scores once i get it built. i cant wait!

[bsouthernau]

after a bit of research of bullet manufacturers i think ive settled for the 200gn sierras.

I'll happily defer to the superior knowlege of anyone who's actually done it but I think you'll be struggling to get good accuracy with a 1:12 twist. Most people use a 1:10 with the 200 Sierra.

Barry

[a.JR]

Hi all , I have successfully shot 200Smks in a 13.5 twist , so your 12 twist will be safe a houses.. Also over the years the Sierra 200 match is the most consistent bullet they make if your into checking that sort of stuff.. Maybe not the most efficient through the air but will sure win you matches if it's accuracy your after ....JR..Jeff Rogers

[westernsky]

cheers JR
with consistency being the key in this game, i think ill give them a go. if it doesnt work i can always go back to the 180gn that im using now.

just have to wait on XLR to resend my stock so i can get shooting!

also, does anyone know anything about bushnell scopes. i have the elite 3200 on my 243 and it works a treat, but the elite 6400 on the rum im suspecting has some issues with the recoil shock. thinking i should change to a NF benchrest?

[AlanF]

...does anyone know anything about bushnell scopes. i have the elite 3200 on my 243 and it works a treat, but the elite 6400 on the rum im suspecting has some issues with the recoil shock. thinking i should change to a NF benchrest?

I don't have direct experience with Bushnell, but will just say that you don't see many in F-Class, and this probably indicates they aren't ideal in some way. Nightforce are the most popular, with Leupold, Weaver also quite common. But if I was buying a scope now it would be a Sightron - I keep hearing good reports about them.

In my opinion, if you want to be a serious competitor, then mechanical reliability of scopes is far and away the most important quality to look for.

Alan

[westernsky]

cheers alan
will check out sightron
available funds will dictate what i get i guess.
happy shooting!

[Norm]

also, does anyone know anything about bushnell scopes. i have the elite 3200 on my 243 and it works a treat, but the elite 6400 on the rum im suspecting has some issues with the recoil shock. thinking i should change to a NF benchrest?

Westernsky,
The Nightforce is a good choice for an upgrade over the 6500 Bushnell but I would go with the NXS for a .300RUM.
There is a 5.5-22x50 NXS for sale at the moment second hand here..
http://austargets.com/forum/index.php?topic=314.0

I have a couple of the 6500 tactical's. One was on my .338RUM and another on a .338 win mag. They have proved very reliable but a .300RUM will test a scope.
I did a small write up on the Bushnell 6500 and a Clearidge....

http://www.austargets.com/multiscope.htm[/url]