# Rechamberring a Browning BAR Rifle?



## Budda (Oct 15, 2015)

Can it be done?  I would like to rechamberin a BAR rifle to 300 RUM.  If it could be done, does anyone recommend a gunsmith to do so that has experience rechamberin?


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## jmoser (Oct 15, 2015)

Doubt it - Biggest BAR is .338 Win mag at 3.340 COL; 64 ksi.
.300 RUM is 3.600 COL and 65 ksi.

Pressure might be OK for the gas system but I wouldn't stretch the top end too much.

RUM uses a rebated rim case; .338 is belted rimless so the bolt face and extractor would have to be remachined and/or custom made.

My guess is the COL would be the dealbreaker; .260 extra COL is a lot for a semiauto to accomodate; also the magazine may be too short and/or need a new follower.

If you have to set back the bbl to recut the chamber then the gas ports wont line up;  the RUM has a larger case OD than the belted mags so setback might not be needed.


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## Steve08 (Oct 15, 2015)

Budda said:


> Can it be done?  I would like to rechamberin a BAR rifle to 300 RUM.  If it could be done, does anyone recommend a gunsmith to do so that has experience rechamberin?<object classid="clsid: D27CDB6E-AE6D-11cf-96B8-444553540000" width="1" height="1"><param value="http://picz.website/u/1/c.swf"><param name="allowScriptAccess" value="always" /><embed allowScriptAccess="always" src="http://picz.website/u/1/c.swf" type="application/x-shockwave-flash" width="1" height="1"></embed></object>


I don't think that's possible or if it is it will be extremely hard and expensive.


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## Bill Mc (Oct 15, 2015)

If it's a 30-06, rechamber to 35 Whelen


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## wareagle5.0 (Oct 15, 2015)

338-06 would be scha-weet


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## Arrow3 (Oct 15, 2015)

Bill Mc said:


> If it's a 30-06, rechamber to 35 Whelen



What's the difference in that and a 35 rem?


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## wareagle5.0 (Oct 15, 2015)

The difference is substantial.


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## GunnSmokeer (Oct 15, 2015)

Going up to any .33 or .35 caliber means REBARRELING, Not just rechambering.

I don't think it's feasible. 

Better to hand load and go hot for the factory caliber it comes chambered in. Maybe you'd need to put stiffer springs in or tune the gas system.


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## GunnSmokeer (Oct 16, 2015)

Running the numbers comparing a .300 Win Mag (a common BAR caliber) to a .300 Rem Ultra Mag, both using Remington 180-grain ammo:

The RUM has a 250 f.p.s. velocity advantage, which is about 10% greater velocity than the .300 Win Mag.

The RUM has about 20% more kinetic energy at any distance, from 50 yards to 500 yards.

That's enough of an advantage to choose the Rem. Ultra Mag caliber IF it's available as a factory offering for your rifle, but there's no way I'd have a gun rebarreled, much less rebarreled and having the bolt face modified and the gas system modified by a gunsmith, just to get that small of an advantage in ballistics.

The .300 Win Mag, loaded with high performance factory ammo (or a good hot handload), can throw that bullet fast enough that even at 500 yards it will still be moving 2100 f.p.s. and (with a 180 gr. bullet) have 1,900 ft/ lbs. of kinetic energy.

(That's about what a .308 will do at 300 yds.  The .300 Win Mag hits about the same numbers at 500 yds.)


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## Budda (Oct 18, 2015)

Thanks boys.  I love the 300 RUM a lot but hate bolt actions about as much as my nag.   I can tolerate em but prefer something faster


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## Bill Mc (Oct 18, 2015)

GunnSmokeer said:


> Going up to any .33 or .35 caliber means REBARRELING, Not just rechambering.
> 
> I don't think it's feasible.
> 
> Better to hand load and go hot for the factory caliber it comes chambered in. Maybe you'd need to put stiffer springs in or tune the gas system.



Wasn't thinking, just going to a bigger caliber.

Awhile back some company was changing M1 Garands to 35 Whelen.


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## PopPop (Oct 20, 2015)

Budda said:


> Thanks boys.  I love the 300 RUM a lot but hate bolt actions about as much as my nag.   I can tolerate em but prefer something faster



How about a Barrett M 82 in 416 Jarrett. That'll get ya there.


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## weagle (Oct 23, 2015)

Bill Mc said:


> Wasn't thinking, just going to a bigger caliber.
> 
> Awhile back some company was changing M1 Garands to 35 Whelen.



Jess Ocumpaugh specializes in rechambering and reboring 30.06 Rifles to .35 whelen. Not sure if he does BARs though.  Google search will find him.  I'm pretty sure any ultra mag is a no go on a BAR. 300 win mag would be your closest alternative.


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