.300 WSM Free bore for 200gr eldx

[Turkey killler]

I am working on a new rifle build and 300 WSM with a long action and 24" barrel. I am looking to shoot bullets in the 180gr to 215gr range. How was wondering what the free bore needed to be to accommodate these bullets. I am using a long action for this rifle build and was wondering what I could get away with and case overall length and what dimensions do I need to tell my gunsmith in order to chamber rifle for the bigger bullets any help and information in this would be, greatly appreciated.

 

[frostop]

My suggestion would be to put together a couple of dummy rounds with the bullets you intend to use seated to the approximate depth that you want to run them and give those to the gunsmith and he can adjust the freebore accordingly.

 

[Rotten]

I would make absolutely clear how much free bore you want with your longest bullet. I made up 2 dummy cartridges when I had my 270 wsm re barreled for a faster twist rate.
I wrote down I wanted .02 freebore with the 175 gr. Tipped game changer. What was delivered was .750 freebore. Basically a 140 gr bullet would be completely out of the case before even making contact with the lands.
They did however make me a new barrel with what I wanted but still can't get the velocity where I think it should be. Don't know why. I'd ask your gunsmith on his opinion as far as freebore with the longest bullet you plan on using. Had two rifles re barreled by 2 different companies and none of them even responded to my request about freebore. The other rifle was a 25 creed that came out perfect besides not responding to my asking. Anyway good luck with your wsm. I like them but seem but not worth the hassle. IMO

 

[frostop]

I'm in the same boat but I'm going to be doing my own on a medium action. 270wsm with the 165 ablr

 

[Rotten]

I'm getting really good accuracy out of the 165 ABLR
Using Retumbo in my 270 wsm. Really want to try it out on elk this year just wish I could get the velocity up past
2850 fps. I'm at 2760fps but even at that it's still carrying enough energy out to 600 yards. Which I won't shoot at game that far. Only milk jugs

 

[frostop]

I just tore down a 270wsm on a Ruger short action that I'm converting to 6.8 western which is going to one of my grandsons.
It had a 26" sendero barrel on it that I was getting right at 3000fps out of the 165ablr, really hoping that I will get close to that out the new rifle.
It's going to be on a Vesper medium action with a proof 24" barrel, needed to light things up a little.

 

[Rotten]

What twist rate did you have on the barrel for 3000 fps with the 165 gr ? I had a post about my pac nor barrel not being able to get good velocity out of it. If you don't mind sharing your load info for that. I can only get 65.3 gr of retumbo with the 165 ablr. And then the bolt will stick very bad. Velocity like I said previously was around 2760 - 2800 but I think my pro Chrono is crapping out. I chronograph the factory nosler 140 gr accubonds at 3040 box says
3100 fps.

 

[frostop]

My pacnor barrel is pre pacnor fire, not sure if that would make any difference.
I will double check my info when I get home tonight!

You should be getting better than that, guys are getting better than that out of a 6.8 western

 

[AkBirder300]

I'm shooting that 200gr ELDX in a SAAMI spec chamber and am happy with it, you might not need to add freebore unless you have a specific velocity goal

 

[Rotten]

Yeah I know is driving me crazy why the velocity is so low. I'm getting a gouge in the brass also that I think is the reason for the bolt sticking.
But I have polished the chamber looked at it with a bore scope measured the bore and I can't figure it out. The only thing that seems off is the back of the brass is .005 bigger than when measuring brass fired in the original barrel. I don't think that would cause higher chamber pressures.

 

[AkBirder300]

Have you tried different brands of brass? ADG might serve you better if experiencing expansion with softer brass.
Do you mind sharing powder and velocity you're currently seeing? I'm at a usable 2730fps using StaBall 6.5 as I had no other uses for it and it groups really well