Hey Guys,

New to the forum and also to the whole rebarrelling thing. I'm wanting to do a rebarrel on a BLR 7mm or 300wm to .458cal for use primarily on buffalo.

I have searched and seen quite a few threads on here about BLR rebarrels and people wanting to do them but cannot find any real results on how they've turned out or any limitations incurred.

I plan to buy a 300wm or 7mm BLR, ideally inthe takedown model and was originally thinking 458wm as I hear many have done this, until I discovered the 458AccRel. I figure I'd sacrifice 1 less cartridge in the magazine for Lott like ballistics.

Does anyone know if anyone has done this in a BLR 458AR? Will it handle the pressures? Have been told that there may be bolt throw issues.

I'd also like to hear about any other big bore BLR rebarrels and if anybody came across anything tricky. Calibres I'm considering are 458AR, 416AR, 375 Ruger ideally.

Any help would be much appreciated.

For the record my heart is set on a lever and recoil doesn't worry me I'm 6ft and big framed, it'll be used hunting and I've never felt recoil on a hunt, for load development I can easily have access to a lead sled if required.

Thank you guys, Mark

Maybe PM Jeffeosso, the inventor of the 458 Accrel. He is a Moderator here.

Howdy Mark,
I am complimented that you would consider my carts for your project, thank you.
458 AccRell - Will it work? Oh yeah - but is it worth the effort?

458 AccRel - it's the king of the carts you have listed - easy to make brass, and whomperstomper power -- it's EASY to match/beat the 458 lott

416Accrel - don't bother, do the 416 Ruger - the AccRel is a larger case, and I think "better" - but 100FPS isn't worth the hassle of the 'cat - the Ruger is a GREAT round

375 ruger - this goes double for what I said on the 416 ruger, as i designed the 375 AccRel, made up a couple cases, and decided the 375 space was too crowded

other choice - 458 winmag - easier to feed in the BLR mag, and a bit tamer recoil than the 458 AccRel ...

let me know how I can help
j

I re-barreled one to 416 Taylor and another to 358 Norma. Both worked out just fine but the owner of the Norma insisted on overloading it until the locking lugs set back enough that the rifle was ruined. While I like the concept, I don't particularily like the BLR as the basis for a dangerous game rifle. Regards, Bill

Thanks for the replies guys.

Jeff thanks for the info.

-416accrel Agree re not being worth the hassle

-375 ruger is a serious contender for me and if I dont do it this time around I will build a takedown blr in it in the future. An excellent backpack hunting rifle to smack the Victorian Sambar deer dead and also usable as a 1 size fits all rifle in Africa.

-458accrel my reasoning is I wish to go heavy for calibre and use the 550gr woodleigh and would like to get it going to 2200fps. I don't thik thats possible with the 458win but should be with yours if it's going to be matching / exceeding the lott. Do you know what the pressures will be like to achieve this and is it feasible in a blr? The action will be from a 300win rated to 64k psi.

Bill that's some excellent information about the 358norma ruining the lugs. Maybe my ambition of running 550gr woodys at 2200fps will result in the same problem. Glad the taylor went well. Besides switching out the barrels what other work was needed?

Thx guys, Mark

Mark,
if loaded within reason, the key thing I would worry about is bolt thrust - which is normally a double rifling building concern - the accrel does have a greater (though not much) bolt thrust at same pressure, due to .550 vs .532 nominal -- well, you can do the bolt thrust calcs, it's pretty easy

i don't recall that I have used 550gr woodies in my rifles -- though 500 grains at well over 2300 (pushing 24000) in 21" barrel wasn't hard

what pressure? they haven't been pressure tested, but i am NOT a bold reloader and quickload didn't show me stupid pressures.. i have NEVER pushed the Accrel's into "pierced primer" pressures, and didn't publish any loads, on ammoguide, that resulted in hugely crushed primers/sticky bolt/ etc ..

a takedown BLR in a major caliber really sounds cool! 18" barrel? but, in 25 to 16", my powder recommendation would still be h335/tac

Hey Jeff,

Thanks for the reply. Please excuse my ignorance but I am also fairly new to reloading and although I know what bolt thrust is I haven't done any calcs before. Google shows me 2 formulas one with the internal area of the case head and another with the external.

Thanks to a quick quick google I found a table on wikipedia (using external case head) showing a 300win example as having 56K N bolt thrust and the 300wsm as 67.5K N which is more than the 375/416 ruger examples they have listed at 60.5K N. I'll be building on either a 300win or 7mm rem platform but they also make BLRs in 300wsm now, so I figure they should be built to withstand the 67.5K N safely.

I don't have QL to be able to see an estimate for chamber pressure with the 550 woodies would be at 2200fps to be able to estimate the bolt thrust using that combo. But if you're saying you got the 500s moving close to 2400 in a 21" barrel and your not a bold reloader with no pierced primers or sticky bolts, it sounds like it should be doable.

I'd love for it to be in a real short 18" barrel but I think to be on the safe side to be getting the speeds I'd like I'll probably be looking at something more like 22/23".

Anything I'm missing here?

The real hard part is finding a takedown in 7rm or 300wm here in Aus!

Thanks, Mark

*PS after typing this I went back and realized that the table also has the 300rum listed as 66K N thrust. Being that the 458AR is basically a shortened rum case and that case length has no bearing on thrust value then thrust should be the same as the rum. Which is less than 300wsm slightly so in theory if they are building them in 300wsm the lugs should be able to to cope. I know its on a shorter action platform but I imagine they'd be using the same bolt and lug system for calibers using the same bolt face from an economical perspective it would make sense for them to do so - I think.*

Bolt thrust calculation requires only peak chamber pressure (say SAAMI-specified maximum) and case head inner area. For 416 Ruger for example estimated bolt thrust is -

62,000 lb/sq in x pi/4 x (0.43 in)^2 = 9000 lbs, and which the bolt lugs are designed to safely withstand.

Great news!
There is a 458 AccRel reamer in Oz, just in case you are wondering - the internal thrust calc is likely the better one to use!

i likely wouldn't go 23" in a takedown ..

Maybe consider the 450 Marlin BLR. Should be capable of firing a 400gr solid at 2100 fps. Think I might need one. In addition to my 358 Win.

https://www.browning.com/produ...inless-takedown.html

358 Win


450 Marlin

Hi there 4sixteen. Can you tell me, are the guts in the stainless made of carbon steel, or something else?

^^

PM sent.

So here's one possible solution, don't even need a new barrel:

1 - Get a 450 Marlin, and possibly a 300 WSM bolt head (see below).

2 - Get it rechambered to 458WSM.

3 - Get a 300 WSM magazine.

I have looked into this a little, but quit when I could not determine that all the BLR short action receivers were the same. That would be the key.

Also, you might have to get a WSM bolt head, as the WSM rim size is a little larger than the 450 Marlin rim.

A 458WSM will duplicate 458WM ballistics. Good luck from a 7 lb rifle with this one.

That's a beautiful gun 4sixteen. Thanks for the formula. Do you know the amount of pressure the lugs in the BLR can handle? I haven't been able to find that anywhere.

Good idea sjmci, but with the availability of parts here in Australia I'd be much more confident just swapping a barrel over.

Jeff pm sent just a couple questions re Accrel

Thanks guys

BLR bolt lugs are designed to withstand shear stress generated from bolt thrust by SAAMI-specified maximum chamber pressure of the round for which the rifle is originally chambered by Browning.



Note maximum specified chamber pressure for 450 Marlin and 7mm Rem mag. Both rounds have 0.532" case head diameter so both BLRs probably have the same action. 450 Marlin maximum operating pressure probably held lower because the round was originally designed for use in Marlin 1895 rifles. BLR Marlin 450 action should be stronger than 1895 action so might safely withstand higher chamber pressure for enhanced muzzle speeds.

Heard anecdotally of a BLR 7mm Rem mag re-barreled to 416 Taylor. Assumed action remained the same. Apparently capable of safely firing full on loads. Maybe not surprising since both rounds have about the same maximum operating pressure and same case head diameter?

BLR 450 Marlin should be interesting to handload. Seems factory loads probably held low at 43,500 psi intended for use in Marlin 1895 and Winchester M94 rifles. Properly handloaded BLR might be safely capable of 150 to 200 fps higher muzzle speeds over factory ammo at load pressures much higher than standard.

https://www.hornady.com/ammuni...erevolution#!/#specs

https://www.buffalobore.com/in...product_detail&p=281

https://saami.org/wp-content/u...-14-Posting-Copy.pdf

Buy a BLR in 30-06 & rebore/ rechamber or rebarrel to 400 Whelen. Have a friend that has one & it works very well.

Thanks for all the great info and replies guys

450 Marlin alternative: handloaded approaching 458 American maximum safe pressure might be safely possible. Probably same 458 Win mag 60,000 psi maximum? Maybe a bit higher speeds because 450 Marlin case is 5% longer.

500gr at 1800 fps? Going to find out. 450 Marlin BLR stainless laminate takedown acquired.

https://loaddata.com/Cartridge...Jacketed-Bullets/921