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Rechamber .358 Win to .350 Rem Mag

17K views 27 replies 15 participants last post by  Ole1830 
#1 ·
I have two BLR's in .358 Winchester and am considering rechambering the new '81 Lightweight to .350 Remington Magnum. I have been thinking about this ever since I bought the rifle earlier this year but have been holding off because of the small gain in velocity attainable, about 150-200 fps.

Today I was surfing on the accuratepowder.com web site and pulled up the reloading data on the .350 RM. I was surprised to see a velocity of 3008 fps out of a 20" barrel for the 200 grain Hornady spire point bullet with 60 grains of AA2520. The most that I can get out of my BLR and stay within pressure constraints is 2600 FPS. That's a gain of 400 fps over the .358 Winchester with the same bullet. That got my attention and renewed my interest in the conversion.

I have three questions:

1. What's the highest velocity that you have attained with your .358 Winchester and a 200 grain bullet. Please indicate load data and barrel length.

2. Same question for the .350 RM. Can you really get 3000 fps out of a 20" barrel with a 200 grain bullet and stay at or under 53,000 CUP?

3. Who is a good and reasonable gunsmith to perform the rechambering?

Thanks in advance,
NITRO
 

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#2 ·
I'm not a BLR expert, you will need to know wha pressure the BLR is proofed to. A 358 SAAMI pressure limitls are around47000 CUP and the 350 62000 or so. if it could be done, your bolt face would have to be opend abput .029 each side, along with a re chamber, and then work the magazine over to feed the larger round. Both ruger and Remington list te 350 in thier 2006 catolog. I'd just buy a new gun if it were me. I have a 350 M700 classic and love it.
 
#3 ·
Nitro I believe your looking at more of a job than is feasable, when you consider the cost of "gunsmithing" etc. Also those things that can and do happen along the road with your rifle, while the job is supposed to be getting done OK.

I would as the other poster suggested, go out an purchase another rifle to suit my wants and needs. Then you have a warranty and haven't lost anything along the wayside. ;)
 
#5 ·
Nitro,

I've one of each, and would recommend leaving the 358 as is, and getting a 350 seperately. I seem to remember some of the 81 358s developing cracks after serious use, and I thought Marshall said something about that, way back in the day. Shooting one to 350 pressures would be some pretty serious use.

That 350 60 grain 2520 load shoots really straight, I was both surprised and delighted. Recoil is there, and would be brutal in an 81- but it does take the 350 into the long range class.

2520 didn't do nearly as good with the 358, but I may get around to trying it out again, somewhere down the road, but not in the short term. I wrote Accuratte about it, and they advised me that 2520 did better close to max, and I beleive it.

Good luck friend, I hope that it works out for you.

Steve
 
#6 ·
NITRO,

Wonder how that belt would affect cartridge feeding and cycling. As far as BLR conversions, check out Z-Hat Custom Rifles.

Whitehunter35 ... never heard of the .358 BLR problems. Seems like there would have been problems with other BLR's as well then, not just the .358W. If they are chambering for the WSMs, etc. Unless they make a significant difference in the actions for them ... or perhaps these problems were a case of overly hot loads fired over time? Just me rambling :).

I think a better conversion for a .35 in the BLR would be the .35 Whelen from a .30-06 BLR action ... of course, you probably don't have one of those handy on your gun rack.
 
#7 ·
I emailed Z-Hat about the rechambering a BLR LW from 358 to 350 and using a BLR 450 Marlin magazine and got the following response from Fred Zeglin:

"The 450 Marlin magazine might be an easy solution but the 358 magazines might work with the 350. It would be easy to test. The rechamber work on the factory barrel would be $150. The bolt conversion is best done by replacing the bolt head and extractor. I don't think that is more than $40. Let me know what you decide. Thanks."

With round trip shipping, for about $250 I could have a 350 RM BLR LW. What's not to like?

Black tail,
As gringo_loco indicated below, the new Lightweight BLR is chambered in the WSM's so 350 RM SAAMI pressures shouldn't be a problem, especially since the 350 case is smaller in diameter than the WSM's.
I would love to have another Remington M700 Classic in 350 ($$$$) but I let my friend up in the Idaho panhandle talk me out of it. I am sure that you enjoy yours.

Cozy,
Point well taken. A new rifle is a better way to go, but I have a fondness for the BLR and the 350. Another way to go would be to sell my NIB 358 BLR and buy a new BLR in 323 WSM. Then there's resale value, or lack of it. The rechambered 350 BLR would be difficult to sell.

jackfish,
Another point very well taken. The 358 pushing a 200 grain bullet at 2600 fps is all that is really needed, but 3000 fps with the same bullet in a short action lever action is so inviting.

whitehunter35,
The frame cracks were on the older steel framed BLR's, usually in handloaded 358's and other calibers that were rechambered. On these older models, the bolt locks-up into recesses in the frame. On the new alloy-framed LW BLR's, the bolt locks-up into the barrel extension, like the AR-15. It is difficult to convince some folks that the new alloy-framed BLR's are stronger than the steel-framed ones, but they are and by a significant margin. I have some AA2520 but haven't tried it in a 358. It seems a little too slow to get top velocities. My best load in the 358 and the 200 grain Hornady Spire Point is 2600 fps with 49.0C grains of IMR3031 and a Federal 215 magnum primer.

gringo_loco,
Thanks for your suggestion of checking-out Z-Hat but I have already done so as indicated at the top of this post.
I like your idea of having a 30-06 BLR converted to 35 Whelen. I have a BLR in 308 that I recently traded from "matt pair" that is begging to be re-bored to 338 Federal. (Hey Matt. How's the Glock shooting?).
 
#8 ·
NITRO said:
I emailed Z-Hat about the rechambering a BLR LW from 358 to 350 and using a BLR 450 Marlin magazine and got the following response from Fred Zeglin:

"The 450 Marlin magazine might be an easy solution but the 358 magazines might work with the 350. It would be easy to test. The rechamber work on the factory barrel would be $150. The bolt conversion is best done by replacing the bolt head and extractor. I don't think that is more than $40. Let me know what you decide. Thanks."

With round trip shipping, for about $250 I could have a 350 RM BLR LW. What's not to like?


jackfish,
Another point very well taken. The 358 pushing a 200 grain bullet at 2600 fps is all that is really needed, but 3000 fps with the same bullet in a short action lever action is so inviting.
_____________________________________________________
As a 350 Rem mag owner this sounds like a project to dream on. But don't expect 3000 fps for a 200 grainer. If you can get 2700 fps, you'd be doing great, but even that's unlikely in a 20" barrel. Then again...I'm dubious of a .358 pushing the 200 to 2600 fps. Maybe that's "Canadian" fps.

Better order up some Tiger Balm for your shoulder!
 
#9 ·
Leverite,

Please go to the top of this thread and click on the chart in my first post. It is a page from the Accurate Powder web site and it indicates that with a 200 grain Hornady spire point and 60 grains of AA2520, they are getting 3008 fps out of a 20" Douglas barrel. I am aware that if AA can get 3000 fps it doesn't mean that I can get 3000 fps. Might get more, might get less. Might have to stop at something less than 60 grains.

Whitehunter35 shoots this load in his 350 and said that it shoots straight but he didn't indicate the velocity.

Any 350 shooters out there getting 3000 fps with a 200 grain bullet and AA2520 or any other powder? I no longer have a 350, otherwise I would work-up a load with this bullet and powder.

My 358 BLR will avarage 2600 fps with this bullet out of a 20" barrel.
 
#10 ·
NITRO said:
With round trip shipping, for about $250 I could have a 350 RM BLR LW. What's not to like?
Sounds like good pricing. I really am surprised it's not higher.

NITRO said:
The frame cracks were on the older steel framed BLR's, usually in handloaded 358's and other calibers that were rechambered. On these older models, the bolt locks-up into recesses in the frame. On the new alloy-framed LW BLR's, the bolt locks-up into the barrel extension, like the AR-15. It is difficult to convince some folks that the new alloy-framed BLR's are stronger than the steel-framed ones, but they are and by a significant margin.
NITRO, that really is a great little nugget of info. I did not realize Browning had significantly changed their action that much. I did, however, have confidence that the bolt lockup was in steel, and not the Al alloy receiver. Thanks for sharing it with us.

Yeah, that little .338 Federal tempts me too ... wouldn't mind trying that out on a project gun. But alas, I really need to get out and pay some attention to what I've got before adding more.
 
#12 · (Edited)
NITRO said:
Leverite,

Please go to the top of this thread and click on the chart in my first post. It is a page from the Accurate Powder web site and it indicates that with a 200 grain Hornady spire point and 60 grains of AA2520, they are getting 3008 fps out of a 20" Douglas barrel. I am aware that if AA can get 3000 fps it doesn't mean that I can get 3000 fps. Might get more, might get less. Might have to stop at something less than 60 grains.

Whitehunter35 shoots this load in his 350 and said that it shoots straight but he didn't indicate the velocity.

Any 350 shooters out there getting 3000 fps with a 200 grain bullet and AA2520 or any other powder? I no longer have a 350, otherwise I would work-up a load with this bullet and powder.

My 358 BLR will avarage 2600 fps with this bullet out of a 20" barrel.
I've never used AA powders, but I will have to get some AA2520 for a try. But I know my 673 won't chamber a 2.8" round. I'm limited to about 2.75".
 
#13 ·
leverite said:
I've never used AA powders, but I will have to get some AA2520 for a try. But I know my 673 won't chamber a 2.8" round. I'm limited to about 2.75".
DId some checking in a 1991 Accurate Arms loading manual which actually lists loads for both the 358 and the 350 Rem mag.

For 200 grain bullets their hottest load is with 2015 powder:
in 358...49.0 gr for 2669 fps (18.5" Ruger 77)
in 350 Rem mag...60.0 gr for 2998 fps (22" Rem 700)

the 2520 max loads;

358...49.0 gr for 2393 fps
350 RM...63.0 gr for 2898 fps

Those are much hotter than any other loads I've seen for either cartridge. Would be curious if any have tried these AA powders
 
#14 ·
I've thought of doing this but adding a 24" barrel and getting the weight up to about 8lbs to help with recoil. But a new barrel will definitely add money to such a project.

I've thought a matching pair of BLR's with 24" barrels in .358 and .350 Remington would give you modern Winchester 71's. And in the case of the .350 Rem would sure increase the fps over the .348.

I love the look and handling of my Winchester and Browning 71's with the 24" barrel. Two BLR's in the same configuration in .385 and .350 would sure be fun and great hunting rifles.
 
#15 ·
bob wilson said:
With round trip shipping, for about $250 I could have a 350 RM BLR LW. What's not to like?

or a 358wsm if your really adventurious,for same price
.

Hey Bob,

Good suggestion, but I am already flinching at the thought of a Lightweight BLR in 350 RM. The 358 Winchester BLR weighs 6.5 lbs. out-the-box. Add scope, mount, rings ammo and sling and the package will weigh about 8 lbs. Here is how the approximate recoil energies stacks up:

358 Winchester: 20 ft-lbs. VIGOROUS. 30-06 CLASS.
350 Rem Mag: 30 ft-lbs. YIKES.
35 WSM: 40 ft-lbs. MEDIC! MEDIC! MEDIC!
 
#16 ·
NITRO said:
.

Hey Bob,

Good suggestion, but I am already flinching at the thought of a Lightweight BLR in 350 RM. The 358 Winchester BLR weighs 6.5 lbs. out-the-box. Add scope, mount, rings ammo and sling and the package will weigh about 8 lbs. Here is how the approximate recoil energies stacks up:

358 Winchester: 20 ft-lbs. VIGOROUS. 30-06 CLASS.
350 Rem Mag: 30 ft-lbs. YIKES.
35 WSM: 40 ft-lbs. MEDIC! MEDIC! MEDIC!
You might consider a limbsaver or other high tec recoil pad. Depending on how your feel about porting that would also be a consideration. I've used magna-port on both a 44mag and a Rem 8mm mag. This only gives you about 20 percent recoil reduction, but it makes a big difference in felt recoil. Got one of the Taurus stainless trackers in 41 mag and the factory porting makes a real difference in the 35 oz gun.
 
#17 ·
leverite said:
DId some checking in a 1991 Accurate Arms loading manual which actually lists loads for both the 358 and the 350 Rem mag.

For 200 grain bullets their hottest load is with 2015 powder:
in 358...49.0 gr for 2669 fps (18.5" Ruger 77)
in 350 Rem mag...60.0 gr for 2998 fps (22" Rem 700)

the 2520 max loads;

358...49.0 gr for 2393 fps
350 RM...63.0 gr for 2898 fps

Those are much hotter than any other loads I've seen for either cartridge. Would be curious if any have tried these AA powders
.

Leverite,

After hours of surfing the web, fliping thorugh reloading manuals and reading your post, I have come to the conclusion that is not very likely that a 350 RM will launch a 200 grain bullet at 3000 fps with 60.0 grains of AA2520. The burning rate is too slow. As you indicated, 63 grains of a faster powder like AA2015 can, so it stands to reason that a slower powder like 2520 will attain "something less than" 3000 fps velocity with a 60 grain or even a 63 grain charge.

The burning rate of AA2520 is similar to IMR4064, Varget, N-202, and IMR4320 and it is slower than Accurate 2015, 2230, 2460 & 2495, IMR 3031 & 4895, Hodgdon Benchmark, H322, H4895, H335 & BLC-2 and Winchester W748. These medium burning rifle powders are all sutible for loading 35 caliber rifle cartridges.

I don't think that the 350 RM case can hold enough AA2520 to get 3000 fps with a 200 grain bullet. One would have to go to the .358 Norma Magnum to do so.

If anyone agrees or disagrees, please chime in. This is a learning experience for most of us.

MAYBE SOMEONE FROM ACCURATE POWDER CO. CAN CONTRIBUTE TO THIS THREAD.
 

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#18 ·
faucettb said:
You might consider a limbsaver or other high tec recoil pad. Depending on how your feel about porting that would also be a consideration. I've used magna-port on both a 44mag and a Rem 8mm mag. This only gives you about 20 percent recoil reduction, but it makes a big difference in felt recoil. Got one of the Taurus stainless trackers in 41 mag and the factory porting makes a real difference in the 35 oz gun.
.

Idaho Bob,

One of my BLR's in .358 Winchester has a muzzle break and it works wonders. Felt recoil is about like my Marlin 336SS in .35 Remington. The brand is "Quiet Brake". It's not quiet but is better than any other brake that I have tried.

I have a Limbsaver pad on a Winchester/Miroku 1886 in 45-70 and it is a big help with heavy cast 405-460 grain loads.

My Taurus M450 super-lightweight snubbie in 45 Colt is ported and that too tames the muzzle flip and recoil. It only weighs 19.5 ounces and with a 255 grain cast bullet at 1000 fps, it is a handfull. The ribbed rubber grips also help.

All good ideas Bob, but the biggest problem is the stock on the BLR. BTW, it seems like the pistol grip stocked BLR has less drop than the "straight" grip stock, but according to the Browning web site they are identical. Drop at comb 7/8", drop at heel 15/16". Check out the photos here and see what you think.
 

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#19 ·
Nitro...regardless if you can attain the elusive 3000 fps w/ a 200 grain bullet, I think your idea of converting to 350 Rem mag is very interesting.

Consider this...instead of reaming to 350 rem mag, ream out the .358 chamber to a 300 WSM or a 325 WSM size (I don't know if they are the same dimensions, as I haven't seen dimensions on the 325 WSM...obviously the necks will be different). I believe both the WSM's are chambered in the BLR short action.

The advantage is more case capacity and plenty of brass around for many years. The BLR .358 barrel may not be meaty enough at the chamber for this, but if it's the same barrel profile as the 300 or 325 WSM barrels, would think it would be OK.

waddayathink?
 
#20 ·
The 35 Calibers

I prepared these charts on ammoguide.com. It is a great site for comparing different calibers and obtaining reloading data on standard and wildcat cartridges.

http://www.ammoguide.com .
 

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#21 ·
I don't know if you've thought about it, but altering the magazines to fully function could be the achilles heel of the whole project. Owning 3 BLR's, I see no way you can open up a .358 magazine to anything larger. Browning never made any of the short magazines feed a belted case, only the long ones. I'm with leverite on this one. It would be easier and cheaper to sell this one and buy a .325 ready to go.
 
#22 ·
Blackhawk44 said:
I don't know if you've thought about it, but altering the magazines to fully function could be the achilles heel of the whole project. Owning 3 BLR's, I see no way you can open up a .358 magazine to anything larger. Browning never made any of the short magazines feed a belted case, only the long ones. I'm with leverite on this one. It would be easier and cheaper to sell this one and buy a .325 ready to go.
.

Browning chambers the 450 Marlin in a short action BLR. Using the 450 magazine should solve the problem since it is a very similar belted case.

Fred Zeglin at Z-Hat told me that the 358 magazine might work with a little alteration. He said that if I sent him the 358 BLR for conversion he would try to use the existing magazine.

A new rifle in 350 RM will cost $550-$650 plus tax. The conversion will cost:

Rechambering: $150.
Bolt work: $40.
Magazine (if needed): $50.
Round trip S&H: $40.

Total:..............$250. to $290.

$350-$400 more gets a new gun. Good point, Blackhawk44, but I will need that money to buy a good scope, dies and brass.
 
#23 ·
leverite said:
Nitro...regardless if you can attain the elusive 3000 fps w/ a 200 grain bullet, I think your idea of converting to 350 Rem mag is very interesting.

Consider this...instead of reaming to 350 rem mag, ream out the .358 chamber to a 300 WSM or a 325 WSM size (I don't know if they are the same dimensions, as I haven't seen dimensions on the 325 WSM...obviously the necks will be different). I believe both the WSM's are chambered in the BLR short action.

The advantage is more case capacity and plenty of brass around for many years. The BLR .358 barrel may not be meaty enough at the chamber for this, but if it's the same barrel profile as the 300 or 325 WSM barrels, would think it would be OK.

waddayathink?
.

The 300 WSM necked-up to .358" is called the 358 Sambar. Below is a scanned page from "CARTRIDGES OF THE WORLD", 11th edition, 2006 by Frank C. Barnes.
 

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#25 · (Edited)
Swany said:
Either way you are talking about an 06 case capacity, the good old much wildcatted .284 case bumped up to .358 is still a good option in a levergun running the approx same case capacity.
.

I have considered the 35-284 because no bolt mod would be required. It has the same rim diameter as the 358 Winchester but case capicity is 5 grains less than the 350 Rem Mag., which equates to approximately 100 fps velocity with a 250 gr. Nosler Partition, when both are loaded to the same pressure; 52,000 CUP.

HERE ARE SOME 35 CALIBER CASE CAPICITIES

35 Remington--------- 51.00 grains of water.
356 Winchester--------56.39 " " .
358 Winchester--------57.19 " " .
30-06-----------------66.58 " " .
35-284----------------67.29 " " .
35 Whelen-------------70.89 " " .
350 Rem Mag--------- 72.25 " " .
300 WSM--------------78.64 " " .
325 WSM--------------79.13 " " .
35 WSM-estimated-----79.65 " " .


Note that there is less than one grain of H2O capacity between the .356 and .358 Winchesters. What happened to the often touted difference of 5-6 grains between the two? It is said to be in the case wall thickness. However, they are almost identical, but that's a subject for another thread which I will initiate, unless the subject has already been posted. I'll give it a couple of days then go for it.

Meanwhile, back to the 35-284. The problem with it is the same as the 35 WSM / Sambar. No factory ammo. Since I am a hand loader, that in itself doesn't concern me. The resale value/desirability of the rifle will be higher chambered in a caliber that ammo is available for, even if it is just one factory offering.

Anyway, an elk at 200 yards won't know the difference when hit with a 250 grain Nosler Partition from a 35-284 @ 2400 fps, 350 RM @ 2500 fps or 35 WSM @ 2600 fps (BLR 20" barrel. Velocities higher in a 24" barrel). NOTE: Velocities at muzzle.

Is all this really worth it? Will that same elk at 250 yards know the difference when hit with that same 250 grain NP with a 358 Winchester @ 2250 fps MV. I really don't know. But that's where the fun comes in. Finding out.
 
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