Reloading for a Browning BAR 300 Win Mag

Earnhardt

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I've been reloading for a while now for a couple of 338 Edge's, 300 RUM, and 6.5 CM's...
And reloading for AR10/LR308 has been interesting....

But I'm looking for an EASY button on this one....

Any inside tricks for reloading for a Browning BAR- BOSS 300 Win Mag?
I'd like to stick with the 168 & 178 ELDs, since I'm confined to the COAL mag length restriction cartridges

Any powders to turn to with these bullets?
Any powders to stay away from?
Any sweet spot/go-to loads when reloading for the Browning BAR 300 Win Mag?

Thanks!
 

Vol1975

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H1000 and a flat base bullet workEd good in mine. Interlock flat base or accubond 180 grain pushed around 3000 FPS. I ran .003 bullet pinch on autos.
I could not though get it to shoot much more than 1 inch group but it was a good hold over killer out to 400 yards for better part of a decade. Mine didn’t have a break and I sold it because of that.
but for a tree stand gun and general hunt it was good enough for an auto killer.

also had some luck with 4831sc powder in bullet above 180 but speed was slower.
 

david g ranes

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I have 2 bars with the boss don’t kid your self they work I do have to use a small base die for my 243 sometimes it would not quite close the bolt all the way bu now no problems. David
 

Jpron

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I have a bar ll without a boss. I’m running imr 4350 with 165 gr sst. It shoots good enough for a semi auto
 

Earnhardt

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Is there a certain bullet weight maximum where the gas system starts to malfunction/gun jams?
 

DangerRanger

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I think your mag length is going to limit you for big long bullets more than anything. I doubt it will have cycling issues specifically due to billet mass.

interested in your results I load for one in 3006 andhave a 300 mag I’d eventually like to also

I’ve found mine is not not picky at all about reliably cycling so far
 

Earnhardt

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When reloading for various AR10 rounds, trying to find a happy medium can be difficult with the various buffer and BCG weights, as well as adjustable gas blocks etc...
that’s why I ask...
Thanks guys
 

david g ranes

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I’ve always shot ballistic tips in mine I wouldn’t think you would have any problems if you stay in the bullet weight your barrel twist was manufactured to use try several loads see what shoots best and then tweak the boss to improve your accuracy I don’t use the sweet spot browning recommends start at the bottom and back it back out a little at a time then you will be going only one direction instead of back and forth like they recommend. David
 

Upsidedownjack

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Well, loading for my 300 WM for some 25/30 years been doing (H-1000) 79* gr with CCI 250 primers and Nosler 180 gr blalic tips. Have worked for me and Elk from +/- 50 yds out about 800+/- Has been a very good load For this gun! Winchester #70 “win lite”. KDF break.
Now working with a Baurgra (HMR-PRO) also in the 300 win Mag! A little different with this gun. Not settled in yet, but soon!
 

Stammster

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I’ve got a BAR, but in Win 270.
I had issues with H4831SC with anything above moderate book loads. The cycle timing was off, and the brass rims got beat up pretty bad. Also the ejected casings were all over the place. At low charge weights the gun cycled fine, and all spent casing fell within a few feet of one another.

I don’t have this problem with faster powders - driving the bullets at similar speeds as to when the H4831SC caused problems.

Surprisingly RL26, although a slower powder than H4831SC, didn’t cause ejection issues until I was at max.
 

blvette75

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Oct 16, 2013
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I don't reload your bullet weights but a bit heavier 180-200 grain. But if you post what you wind up with will give it a try.

Due to shortage of H1000 been playing around a bit, have found although you may be able to effect the accuracy with the BOSS tuning, found that my BAR 300 win mag likes a COAL of between 3.310 and 3.325, I don't have a BOSS on mine. I found for ejection and feeding I keep my Brass between 2.6050 and 2.6150. I neck size with a Lee and use a Redding body die and have moved away from my Lee seating die now use an RCBS comp die. I may go back to full sizing but currently this appears to work for me. When I purchased my BAR I had stopped reloading for a while and had compared box ammunition when I bought the rifle a few years back. Had recorded COAL and velocity on these different ammo to see what fed and ejected well, and what gave me the best accuracy tried 9 different brands some times multiple weights and types of bullets. For whatever reason my BAR prefers the Remington green 180 grain Core-lokt stuff was consistently shooting about 0.5" 3 shot groups at 100 yards, three different boxes. The Remington Green box were all below COAL target about 3.320 or less none above 3.325. Only three gave consistent sub MOA three shot groups, the Remington, the Nosler ammo in the following paragraph and Federal Premium180 grain accubond. Had old boxes Red box Winchester 150 grain Deer ammunition was also sub-MOA but only shot one group saving these boxes for whitetail, very old boxes(about 20 years old).

Had bought some custom Nosler 200 grain accubond ammunition that my BAR shot well the COAL measured 3.310-3.320 on those and grouped about 50-.75 inches at 100 yards, trying to get better using H4831 and H4831SC not 100% decided but H4831- target looks best at like 69 grain targeting 2800 fps like the Nosler custom. The BAR did not shoot well the Hornady Precision Hunter 200 grain ELD-x, at a COAL of 3.340- speed at-2860 +/- 30 fps grouped about 1.5" and above. For my current loads I am using the federal 215 primers, brass is Federal Prime hunting and trying my blue box federal brass that was a bit of work to size it to match the Prime hunting brass will see how the primer pockets hold up. The next loads will use the Nosler Brass and Hornady Brass.

Also loading 180 grain partition bullets had good luck with these in my Savage the BAR replaced the Savage, original load was 78 grains of H1000 same Brass as above, primers are now with WLRM but may switch back to federal 215. Had two of these old rounds left. When I shot those through the BAR they were touching and hit dead center after scope setup was completed. Currently trying the (cannot find H1000) H4350 and IMR 4350 targeting the Load for 180 grain bullet at a 2980fps velocity had with H1000 out of the Savage. So far best H4350 was 69 grains, and IMR4350 was 68.5-69 grains weighing in grams so converting back to grains for this blog. IMR seemed more accurate but could be me. Will try the Remington green box Brass next, for the next group of loads, so Far accuracy hovering at 1 MOA, a better shooter would probably do better the BAR trigger is heavier than I am used to mine measures about 4,5lbs, I typicaly use a 3.5-3 lb trigger or less on my rifles.

Had my barrel threaded to 5/8 x24 a BOSS is a different thread found out recently since I finally found a vendor that carries the BOSS so looking for a tuner brake with the 5/8 x 24 thread.
 

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