300 WSM AR10

[C-130 Dude]

This thread made me get out my 300 Saum and pound a few targets. What a sweet round in an AR, makes me grin every time.

My 20" barrel sends the 168s at 2850 btw. Nice mild load.

Very nice!

 

[bamban]

I have asked JP several times over the years to make bolts for lefties. No joy. I must say that if you are building an AR308 from ONE manufacturer, timing is easier. But if you use parts from different makers, be prepared for a few headaches. Gas port size, adjustable gas blocks, buffer weights, and spring rates are mandatory issues to get timing just right. Now add a can or muzzle break and you just added another wrench in the works. Yes it can be done. But it will take a bit to wring out. Stay safe and have fun.

I chamber my own barrels from blanks. Not dealing with production barrels.

My 16.5 AR10 308 is suppressed using legacy Surefire FA762SS. I use the same suppressor on a couple 20 inch AR10 in 308s that I shoot on occasion. No adjustable gas block. Besides 6.5CMs I chambered for some friends I also chambered a 243 for one of them. No issue with gas system, the problem is with those long pointy 6mm bullets getting wedge between the barrel extension bottom lugs . Found a special barrel extension, solved the problem. Luckily both BE threads timed the same, very rare

Chambered a few large frame ARs for friends, and chambered close to 100 AR15 barrels of varying length, chamber, contour, and gas block. Between me and my buddies we have 5 MK12 SPR with AEM5 suppressors. They are using adjustable gas block. Since mine is strictly suppressed I drilled/ream the gas port size so I don't have to use a gas block. We use GI MK262 Mod1, we dont deal with different load/pressure.

The 300WSM is just a new thing for me.

Lots of suppliers talk about brass pattern as a timing thing. Since shooting the AR15s in service rifle, some of we've modified either the ejector or the spring so the spent brass land on a nice pile at 1 o'clock within arms reach. Nice feature when shooting sitting and prone. Reason, so you don't have to worry about your brass getting all mixed up with others on the line.

Thank you for your input.

 

[BillLarson]

Go with either rifle +2 or +3 gas length, with an adjustable gas block
-Minimum 9.3oz up to the XXH 15oz -Slash heavy buffer.
Tubbs flat wire
-Use loctite 620 on the barrel extension
-TO ME the heavier the over all weight on the gun, the better it runs
-go with a mid weight bullet at average speeds
-use medium the faster burning powders
-a good brake really calms down the over all action/movement of the gun

Now that information alone could save the man 1000,s$....
Thank u for your input.

 

[bamban]

This thread made me get out my 300 Saum and pound a few targets. What a sweet round in an AR, makes me grin every time.

My 20" barrel sends the 168s at 2850 btw. Nice mild load.

Like that. US Army AMU played with the 300 SAUM, they had a good reason why they decided on the SAUM instead of the WSM. I wish I have the reamer and brass for it.

 

[BillLarson]

Very nice!

How much would a gun like that weigh...???

 

[C-130 Dude]

I chamber my own barrels from blanks. Not dealing with production barrels.

My 16.5 AR10 308 is suppressed using legacy Surefire FA762SS. I use the same suppressor on a couple 20 inch AR10 in 308s that I shoot on occasion. No adjustable gas block. Besides 6.5CMs I chambered for some friends I also chambered a 243 for one of them. No issue with gas system, the problem is with those long pointy 6mm bullets getting wedge between the barrel extension bottom lugs . Found a special barrel extension, solved the problem. Luckily both BE threads timed the same, very rare

Chambered a few large frame ARs for friends, and chambered close to 100 AR15 barrels of varying length, chamber, contour, and gas block. Between me and my buddies we have 5 MK12 SPR with AEM5 suppressors. They are using adjustable gas block. Since mine is strictly suppressed I drilled/ream the gas port size so I don't have to use a gas block. We use GI MK262 Mod1, we dont deal with different load/pressure.

The 300WSM is just a new thing for me.

Lots of suppliers talk about brass pattern as a timing thing. Since shooting the AR15s in service rifle, some of we've modified either the ejector or the spring so the spent brass land on a nice pile at 1 o'clock within arms reach. Nice feature when shooting sitting and prone. Reason, so you don't have to worry about your brass getting all mixed up with others on the line.

Thank you for your input.

Sometimes the brass pattern pile is not the tale of the tape. It's how it feels in relation to how hard the gun cycles. It takes a bit of experience to come to this conclusion. I too had problems with skinny calibers deflecting off the extentions. Judicious use of a grinder and polishing eventually won out. Elbow grease, lots of it. And a lot of patience. Stay safe and have fun!

 

[C-130 Dude]

I chamber my own barrels from blanks. Not dealing with production barrels.

My 16.5 AR10 308 is suppressed using legacy Surefire FA762SS. I use the same suppressor on a couple 20 inch AR10 in 308s that I shoot on occasion. No adjustable gas block. Besides 6.5CMs I chambered for some friends I also chambered a 243 for one of them. No issue with gas system, the problem is with those long pointy 6mm bullets getting wedge between the barrel extension bottom lugs . Found a special barrel extension, solved the problem. Luckily both BE threads timed the same, very rare

Chambered a few large frame ARs for friends, and chambered close to 100 AR15 barrels of varying length, chamber, contour, and gas block. Between me and my buddies we have 5 MK12 SPR with AEM5 suppressors. They are using adjustable gas block. Since mine is strictly suppressed I drilled/ream the gas port size so I don't have to use a gas block. We use GI MK262 Mod1, we dont deal with different load/pressure.

The 300WSM is just a new thing for me.

Lots of suppliers talk about brass pattern as a timing thing. Since shooting the AR15s in service rifle, some of we've modified either the ejector or the spring so the spent brass land on a nice pile at 1 o'clock within arms reach. Nice feature when shooting sitting and prone. Reason, so you don't have to worry about your brass getting all mixed up with others on the line.

Thank you for your input.

Sometimes the brass pattern pile is not the tale of the tape. It's how it feels in relation to how hard the gun cycles. It takes a bit of experience to come to this conclusion. I too had problems with skinny calibers deflecting off the extentions. Judicious use of a grinder and polishing eventually won out. Elbow grease, lots of it. And a lot of patience. Stay safe and have fun

 

[C-130 Dude]

Sometimes the brass pattern pile is not the tale of the tape. It's how it feels in relation to how hard the gun cycles. It takes a bit of experience to come to this conclusion. I too had problems with skinny calibers deflecting off the extentions. Judicious use of a grinder and polishing eventually won out. Elbow grease, lots of it. And a lot of patience. Stay safe and have fun

Sorry for the double post. Mis timed fingers.

 

[C-130 Dude]

How much would a gun like that weigh...???

Mine is 14 lbs with a bipod. 20in barrel.

 

[bamban]

I chamber my own barrels from blanks. Not dealing with production barrels.

My 16.5 AR10 308 is suppressed using legacy Surefire FA762SS. I use the same suppressor on a couple 20 inch AR10 in 308s that I shoot on occasion. No adjustable gas block. Besides 6.5CMs I chambered for some friends I also chambered a 243 for one of them. No issue with gas system, the problem is with those long pointy 6mm bullets getting wedge between the barrel extension bottom lugs . Found a special barrel extension, solved the problem. Luckily both BE threads timed the same, very rare

Chambered a few large frame ARs for friends, and chambered close to 100 AR15 barrels of varying length, chamber, contour, and gas block. Between me and my buddies we have 5 MK12 SPR with AEM5 suppressors. They are using adjustable gas block. Since mine is strictly suppressed I drilled/ream the gas port size so I don't have to use a gas block. We use GI MK262 Mod1, we dont deal with different load/pressure.

The 300WSM is just a new thing for me.

Lots of suppliers talk about brass pattern as a timing thing. Since shooting the AR15s in service rifle, some of we've modified either the ejector or the spring so the spent brass land on a nice pile at 1 o'clock within arms reach. Nice feature when shooting sitting and prone. Reason, so you don't have to worry about your brass getting all mixed up with others on the line.

Thank you for your input.

Sometimes the brass pattern pile is not the tale of the tape. It's how it feels in relation to how hard the gun cycles. It takes a bit of experience to come to this conclusion. I too had problems with skinny calibers deflecting off the extentions. Judicious use of a grinder and polishing eventually won out. Elbow grease, lots of it. And a lot of patience. Stay safe and have fun

Here is the barrel extension I used on the 243 and will use on the 300WSM. They refer to it as big bore.

AR-10 Big Bore LR308/DPMS Barrel Extension

AR10 big bore barrel extensions are machined to match grade standards with integral feed ramp and predrilled locator pin hole for fast, easy barrel installations. Made from 8620 steel and heat trea…

www.triuneprecision.com

 

[C-130 Dude]

Here is the barrel extension I used on the 243 and will use on the 300WSM. They refer to it as big bore.

AR-10 Big Bore LR308/DPMS Barrel Extension

AR10 big bore barrel extensions are machined to match grade standards with integral feed ramp and predrilled locator pin hole for fast, easy barrel installations. Made from 8620 steel and heat trea…

www.triuneprecision.com

Oh yeah. No elbow grease. This looks like it will be a start of a new ext/barrel for me. I actually amplanning on re-barreling my large frame sometime this late summer. My ar308 is on its last breath. You say this is the extention you used on your 243? Are the lug edges radioused smooth?? The ramp area looks nicely releaved. I spent a lot of time working these areas. I may go to 22 or 24 in this time. Haven't made up mind yet. What gas port size worked for you? I ended up with 094 on several ar308 guns. Seemed to be a sweet spot. I switch from can to muzzle break often depending on shooting location. Noise complaints from my neighbors.

 

[bamban]

Oh yeah. No elbow grease. This looks like it will be a start of a new ext/barrel for me. I actually amplanning on re-barreling my large frame sometime this late summer. My ar308 is on its last breath. You say this is the extention you used on your 243? Are the lug edges radioused smooth?? The ramp area looks nicely releaved. I spent a lot of time working these areas. I may go to 22 or 24 in this time. Haven't made up mind yet. What gas port size worked for you? I ended up with 094 on several ar308 guns. Seemed to be a sweet spot. I switch from can to muzzle break often depending on shooting location. Noise complaints from my neighbors.

2mm and no adjustable gas block on 20 inch service rifle with 0.750 journal. 20 is the max length by rulebook, as well as the .750 gas block journal, and no adjustable block.

Which 308 reamer do you use to chamber your barrels?

 

[C-130 Dude]

2mm and no adjustable gas block on 20 inch service rifle with 0.750 journal. 20 is the max length by rulebook, as well as the .750 gas block journal, and no adjustable block.

Which 308 reamer do you use to chamber your barrels?

Haven't got that far yet. May have to send it out. Don't have a usable reamer. More pain

 

[budlight]

When you went with the +2 tube, did you find your gas system and timing going into fits of protest? How did you finally balance it out?

I didn't have any problems. I had reloaded bunch of commercial 308 brass with 2 grains less than the listed max for 150 bt-fmj for testing 45.1 and 2.700 for COL for ease of feed. So they might be approaching 60K psi. chrono speed was just over 2800 fps.

The ejections started out at @ 2 o'clock so I opened the gas block just a little to get right about 3. I've also been lucky with non adjustable gas blocks and just put in rifle length springs for what ever the caliber

I've never have built an AR with problems because I use the best forgings with the latest style of barrel nuts and free float m-lock type hand guards.

In the past I built some piston guns with Superlative gas blocks and the adjustment aren't the best.