Green Mountain 416SS 1.2" Centerfire Barrels Testing

padom · Dec 19, 2023

I've had this pile of Green Mountain 416SS lapped and turned on centers 1.2" blanks here for a while now to test. Some were sent to me by the people at Green Mountain for testing/review and some I bought.

Finally have all 4 chambered up and ready to test. I had them all chambered in calibers I have extensive data on so I can make direct comparisons with the data, loads, etc

All Barrels are Green Mountains top of the line 416SS turned on centers and lapped 1.2" straight blanks.

Here are the 4 Barrels cut by PVA

26" 223Rem 1.2" straight 1-8 muzzle 5/8-24
shouldered TL3
223 Rem Match Eachus
(This is the first barrel cut with my new custom 223 Rem Match reamer I had made to shoot 75/80's with max case capacity and no turn neck... 0.080" freebore 0.253" neck)

26" 6BR 1.2" straight 1-7.5 muzzle 5/8-24
TL3 Shouldered
6BR Eachus
(This is the first barrel cut with my new 6BR reamer 0.105" freebore 0.272" neck)

26" 6.5x47L 1.2" Straight 1-8 muzzle 5/8-24
TL3 Shouldered

26" 308win 1.2" straight 1-10 muzzle 5/8-24
PVA's 175 FGMM reamer
TL3 Shouldered

All Barrels will be shot on my new single shot TL3 action in my fully bedded Revolution benchrest stock, Cortina V2 Tuner, BixN Andy TacSport Pro and Gen3 Razor/Area419 matched rings in Seb Neo rest from the bench.

Trying to take as much shooter out of the equation to see how these barrels really shoot and how they compare to my Bartleins, Kriegers, Mullerworks, and Rock Creeks.

First up I screwed on the 223Rem barrel and wanted to get some rounds down it and some brass fireformed... loaded up the following to zero and shoot today.

I was not judging accuracy today. Just wanted to get 50rd down the barrel. It was 38F while at the range with a sustained 17MPH wind and 35-30Mph gusts. Wind chill was 26F. It was miserable out.

I loaded 25rd of 75 ELD's 24.4gr Varget 0.01 off and 25rd of 80smk 24gr Varget 0.01 off...

I got a rough zero with the ELD and banged some steel. Even in this crazy wind the 75 eld didn't shoot great. Probably around an inch...

The 80smk were shooting really well even with 25-30mph gusts.. I fine tuned my zero with the 80smk and played with a few different tuner settings. Shooting sub half moa out the gate no load development or tuning.

I'll clean the barrel and load up the other 50pcs of brass and do a mini load development with these 80smk around 24gr and see what it likes best. Then do a seating depth test and play with the tuner then I'll take it out to distance.

padom · Dec 19, 2023

Lapua Brass - 205M Primers

80smk 24.0gr Varget - 2828 SD 13
75 ELD 24.4gr Varget - 2912 - SD 9.7

DarinC · Dec 20, 2023

Following along intently. I have a few green mountains and they all shoot even though I get a lot of shit from my buddies about running them.

padom · Dec 20, 2023

Loaded up the other 50pc of 3x fired Lapua this morning.

I loaded 5 foulers 24gr at same 0.01 off the lands with the 80smk... I then loaded a mini ocw 10rd each 23.8, 24.0, 24.2 all 0.01 off lands with the 80smk.

I also loaded a seating depth test with the 24.0gr 80smk load 5rd each.. 0.02 off, touching and 0.005 jam. I already have the 24.0gr 0.01 off groups shot in the mini ocw so no need to load that up in the seating test.

I cleaned the barrel from yesterday's initial 50rd before going back out today. Conditions were much better and more predictable then yesterday's session.. still had a 10-15mph wind but it was consistent and no 25-30mph gusts...

Bottom left corner of the target is my first rounds down the clean cold bore today. The lowest hole in the group at 6 o'clock was the 1st shot ccb... all 5 shots still in the 0.2's.. not bad for a scrubbed clean and cold gun.

Next I worked to the right shooting 2 five shot groups each of 23.8, 24.0, 24.2.. Takeaway so far, 24.0gr Varget/80SMK load hammers out of this GM barrel in all conditions...clean, cold, dirty, hot...it is shooting consistently tight.

Next I shot the 24gr seating depth test across the 3rd row up, working left to right...

This combo likes being closer to the lands vs farther away. While all the groups are nothing to sneeze at...all sub 0.5moa. But 0.01 and closer really stack on top each other.. the 0.005 jam test I knew as soon as I shot that high round it was me. I was timing shooting in between shots of the guy next to me. He broke his rhythm and fired when I was firing that high shot and threw me off..

So far, this Green Mountain 224 barrel is producing very small 5 shot groups at 100yd..

I'm going to load up 50rd of 24.0gr and seat 25 of them to 0.01 off and 25rd to touching and see how they shoot at 200 and 300yd.

Wouldn't hesitate buying one of these blanks for an upcoming build when they are less than $200!

RXS227 27" 223 Cal 1.20" OD 416SS 1:7 Turned BBL Blank

db2000 · Dec 20, 2023

I’m interested in what a couple 10 shot groups will look like. Seems to like that combo! 77 SMK and H4895 has worked great for me. I may have to play with some Varget. It’s been a while in .223.

padom · Dec 20, 2023

db2000 said:
I’m interested in what a couple 10 shot groups will look like. Seems to like that combo! 77 SMK and H4895 has worked great for me. I may have to play with some Varget. It’s been a while in .223.

I need to process this 100pcs of formed brass so maybe I'll just load up all 100pcs and shoot a few 200yd 10shot groups like I do with my RimX barrel teeting...

H4895 and Varget shoot equally good for me in 223rem.. tiny ass groups. I like H4895 because it shoots a little higher velocity with 0.4gr less powder for me. Helps with getting more in that tiny ass case while maximizing velocity.

I just chose Varget for this testing instead of H4895 because I have tons of Varget and only about 14lb of H4895 left... And 8lbers of Varget are on the shelf at my LGS...

db2000 · Dec 20, 2023

That’s a good strategy. I looked back, I’ve never tried Varget in 223. I give it a whirl. 175 SMK and 42.5 H4895 is probably the best 10 shot group I’ve achieved consistently in my .308 bolt. I usually shoot 185 Juggs and Varget performs better for me but a little bigger groups albeit still MOA.

padom · Dec 20, 2023

db2000 said:
That’s a good strategy. I looked back, I’ve never tried Varget in 223. I give it a whirl. 175 SMK and 42.5 H4895 is probably the best 10 shot group I’ve achieved consistently in my .308 bolt. I usually shoot 185 Juggs and Varget performs better for me but a little bigger groups albeit still MOA.

308 with smk and tmk...168, 169, 175, 177 I can't bring myself to shoot anything other than IMR4064 with the accuracy I get

padom · Dec 21, 2023

Got out again today. Conditions were tricky with a switching 5-10mph wind. Much more unpredictable than yesterday. It was really blowing that little 224 bullet around..not the best day for shooting tiny groups at distance.

When the wind did cooperate, I was able to pull out some nice results.

I shot at 200yd, 300yd, 400 and 635yd.

Even with the wind blowing I was able to pull of a sub 0.5moa 10 shot group at 200yd and just over 0.5moa 10shot group at 300yd...

Final takeaway, this barrel shoots great and is a heck of a value at $172... unless your shooting benchrest at the top of the national leaderboard...this barrel shoots better than most shooters.

200yd

300yd

0400yd

635yd

db2000 · Dec 21, 2023

Hell yeah. Very nice.

InnaWoods86 · Dec 26, 2023

padom said:
223 Rem Match Eachus
(This is the first barrel cut with my new custom 223 Rem Match reamer I had made to shoot 75/80's with max case capacity and no turn neck... 0.080" freebore 0.253" neck)

Do you have a print for this reamer.
Looks like a winner.
Thanks

InnaWoods86 · Dec 26, 2023

Looking forward to seeing how these other GM barrels shoot.

padom · Dec 26, 2023

InnaWoods86 said:
Do you have a print for this reamer.
Looks like a winner.
Thanks

It's a JGS 223 wylde reamer print with the freebore adjusted to 0.080" and neck changed to 0.253

Harman117 · Dec 27, 2023

How are you liking the single-shot TL3?

I like the idea of being able to fire anything from .223 sized cartridges to short action magnums without having to worry about feeding from a magazine. Are there any hiccups trying to get the smaller stuff into the chamber?

padom · Dec 27, 2023

Harman117 said:
How are you liking the single-shot TL3?

I like the idea of being able to fire anything from .223 sized cartridges to short action magnums without having to worry about feeding from a magazine. Are there any hiccups trying to get the smaller stuff into the chamber?

I'm loving it actually. So far I've only shot 223rem and 6br out of it and it feeds both like a Swiss watch. I put it together strictly for a test rig to take as much shooter out of any testing of barrels, bullets, powders, etc... fully bedded it in this benchrest stock and its a tack driver. Cycles extremely smooth.

I have a new Green Mountain 308win screwed on it now that up next to test.

padom · Dec 31, 2023

Alright this new 26" GM 308win is screwed on and ready for testing

I have 60rd of FGMM 168smk factory ammo ready to break it in and loaded up some Peterson 308win Palma brass with 177 SMK and 42gr IMR4064... this combo shoots in the 0.2s consistently with many 0.1 five shot groups in my 24" Krieger with Lapua Palma brass...

These are seated 0.005 off the lands where they shot best in my Krieger...

Probably have to tweak my load with this 26" barrel and Peterson brass but let's see.. also, this GM is 1-10 where my 24" Krieger is 1-11.. see if that shows any difference when comparing results

Stay tuned...

padom · Jan 2, 2024

It was COLD and windy today but I got out to get some initial rounds down this 308 barrel.

I shot 80rd of FGMM to get a rough zero and bang some steel then shot some groups. I played with different tuner settings shooting multiple groups with each new tuner setting. There was 1 setting that really stood out.

Going to do load development now with the 177smk and see how much better we can tune it. I'd say this barrel is already proving it shoots. Zero load development and its already shooting in the 0.3's with both FGMM and 177smk handloads... pretty damn good for a sub $170 blank!

RXS3010 27" 308 Cal 1.20" OD 1:10 Twist Turned BBL Blank

100yd FGMM 168gr - multiple different tuner settings 5 shot groups. I didn't bother measuring every group but this barrel was shooting very well with this ammo.

42gr 4064 / 177smk - different tuner settings 100yd

ARShooter91 · Feb 5, 2024

Do you have a bore scope? Curious to see what these barrels look like. Not that it matters if they're shooting that well and not fouling up quick.

padom · Feb 5, 2024

ARShooter91 said:
Do you have a bore scope? Curious to see what these barrels look like. Not that it matters if they're shooting that well and not fouling up quick.

I do. I can post some pictures tomorrow. They shoot great and no they haven't fouled quickly.

Matagorda308 · Feb 6, 2024

Do the GM barrels clean up as easy as Bartlein, Krieger , etc. ? Notice any difference in cleaning?

padom · Feb 6, 2024

Matagorda308 said:
Do the GM barrels clean up as easy as Bartlein, Krieger , etc. ? Notice any difference in cleaning?

Honestly no, I haven't found any cleaning difference. I do nothing different. I cleaned the 308 yesterday, cleaned up just like my other barrels and bore looks great.

padom · Feb 28, 2024

Finally got the 6BR barrel mounted and 50rd loaded up with Varget and 105 Hybrids.

Hope to get out tomorrow and get some initial rounds down it.

FisherT&C · Feb 29, 2024

I just chambered one in 6 BRA for an AI. The customer is a guy I know and have shot with several times. I told him I expect a full report.
I had to use a .2375" pilot bushing; which is the biggest I have. I slugged the bore at .244" so it's definitely on the big side.
The barrel turned and reamed well, and was very straight. I'm very interested to hear how the 6 BR does.

padom · Feb 29, 2024

FisherT&C said:
I just chambered one in 6 BRA for an AI. The customer is a guy I know and have shot with several times. I told him I expect a full report.
I had to use a .2375" pilot bushing; which is the biggest I have. I slugged the bore at .244" so it's definitely on the big side.
The barrel turned and reamed well, and was very straight. I'm very interested to hear how the 6 BR does.

If it shoots anything like the 223 and 308, it will be a great budget barrel. We shall see

padom · Mar 3, 2024

I got out and fired 50rd just to get some rounds down the barrel. No load development. Just loaded up a load from another 6BR barrel. 30.2gr Varget 105 Hybrid 0.020 off

I got it zero @ 100yd and played with some tuner settings. Found a tuner setting it really liked and hammered out 3 groups of 5 that measured high 0.2's to 0.3s...

I'll now do some load development and seating depth testing and see if I can get it dialed in further.

padom · Oct 1, 2024

I have 250rd down this 26" GM 6BR now. What a great budget blank for under $125 on sale!

I did a full on budget session today just to see how it would perform and damn it shot great. Just wanted to see how it would do at 100yd then I'll go shoot some at distance..

26" Green Mountain 416SS TL3 6BR 1.2" straight
6BR Eachus Chamber (.272 neck, .105fb)
American Reloading 108 ELD Pulls $0.18pc
American Reloading MP540 Powder (stick powder similar to AR Comp)
16x fired Lapua
CCI 450

Stupid accurate and amazing consistency with a ES 7.5 and SD 2.9 for this 5 shot group!!

max1840 · Oct 1, 2024

That's an impressive by the rifle, components and the shooter.

padom · Oct 1, 2024

max1840 said:
That's an impressive by the rifle, components and the shooter.

To be clear, I'm testing raw accuracy here to see how this barrel really performs, trying to keep all outside influences away so we can really see what this Green Mountain blank is capable of.

This barrel was tested in a fully bedded benchrest stock on a TL3 single shot action from a SEB NEO and rear protektor bag...

I think the blank shoots

and American Reloading pull down powder and pulls for the win again.

padom · Oct 3, 2024

Next up in the Green Mountain 416SS barrel test lineup is this 6.5cm..

26" Green Mountain 416SS 1-8
1.2" straight
TL3
5/8-24 muzzle threads
BNA TacSport Pro 2 stage
Vortex Gen3 Razor 6-36
Bedded benchrest stock
Chambered in 6.5cm by PVA

padom · Oct 3, 2024

And to continue on the budget accuracy testing I did with thr 6BR...

I'm going to start my testing with this barrel using stupid cheap budget components from American Reloading and see how it does. If it doesn't perform how we expect then I'll switch over to H4350, 130 Hybrids, etc.

American Reloading MP579 (IMR4451)
American Reloading 6.5 130 SMK HPBT Pulls
American Reloading New Primed Nosler 6.5cm brass

357Max · Oct 3, 2024

@padom - Not sure if you see this on your end, but I only see about 1 of ever 4 pictures you post.

Edit something up with PC on my end, they all show on my phone.

Sorry for the side track.

Hickswr · Oct 3, 2024

357Max said:
@padom - Not sure if you see this on your end, but I only see about 1 of ever 4 pictures you post.

View attachment 8516218

Interesting, I can see all 4

padom · Oct 3, 2024

357Max said:
@padom - Not sure if you see this on your end, but I only see about 1 of ever 4 pictures you post.

View attachment 8516218

No every single picture I posted shows on my end on 3 different devices...

JR1200W3 · Oct 3, 2024

I could see all 4.

357Max · Oct 3, 2024

padom said:
No every single picture I posted shows on my end on 3 different devices...

Edited post something up with my PC. Phone is GTG.

padom · Oct 3, 2024

I just got back from putting the first rounds down this barrel. The 100% budget load didn't disappoint and neither did this barrel.

Loaded up 42gr of this MP579 and shot a few groups before banging some steel. Out 50rd down the barrel

Here the first 5 shots down the barrel @ 100yd.

American Reloading MP579 (imr4451)
American Reloading New pulled Nosler primed brass
American Reloading 130 SMK pulls

I shot a few more groups @ 100yd before banging steel with the rest.

db2000 · Oct 3, 2024

padom said:
I just got back from putting the first rounds down this barrel. The 100% budget load didn't disappoint and neither did this barrel.

Loaded up 42gr of this MP579 and shot a few groups before banging some steel. Out 50rd down the barrel

Here the first 5 shots down the barrel @ 100yd.

American Reloading MP579 (imr4451)
American Reloading New pulled Nosler primed brass
American Reloading 130 SMK pulls

I shot a few more groups @ 100yd before banging steel with the rest.

Hard to argue with.

padom · Oct 3, 2024

db2000 said:
Hard to argue with.

Really can't. For a $150 blank, pull down powder, pulled bullets, pulled brass and no load development this setup is nothing to sneeze at and will make 90% of shooters out there very happy.

JR1200W3 · Oct 3, 2024

The problem with most people is everyone thinks they need the best barrel ever made. Every newbie post: "Buying first custom rifle. What's the best barrel?"

I like to dabble with McGowen blanks. Right now I'm shooting a $235 blank in 22GT and it hammers. I placed 5th at the last match I shot with it. Fairly competitive match. Unfortunately I think the population this thread is going to appeal to is relatively small.

DarinC · Oct 3, 2024

I’ve got a couple of them and they hammer as well. Will be watching them to see if I can grab another when they’re in atock

padom · Oct 4, 2024

Every one I've shot so far has shot excellent for the money. Probably wouldn't be the blank I'd be buying to shoot benchrest where every 0.1 counts but for 90% of the shooters out there this blank will get it done and save you money.

When they run that 30% off entire site sale every few months it's really hard to beat

padom · Oct 7, 2024

To finish firing the last 50pc of virgin brass today I did a comparison of the American Reloading MP579 (4451) and 1lb can of never opened actual IMR 4451 I had in the cabinet.

Speeds and SD's are very similar with MP579 having slightly better ES/SD's but MP579 had WAY better accuracy. Actual IMR4451 shot like absolute shit accuracy wise...

I just sized these 100pc of fired brass. Will do a formal load workup now with MP579.

Here the numbers

MP579 (4451)
5 shots each

42.0 - 2795.0 es 20.8 SD 6.9
42.5 - 2828.8 es 56.8 SD 18.9
43.0 - 2862.8 es 36.3 SD 13.2
43.5 - 2908.7 es 32.6 SD 13.8

IMR 4451
5 shots each

42.0 - 2780.4 es 40.7 sd 13.8
42.5 - 2830.9 es 66.2 SD 24.9
43.0 - 2873.8 es 44.5 SD 19.1
43.5 - 2905.7 es 40.4 SD 13.7

drglock · Oct 7, 2024

padom said:
I just got back from putting the first rounds down this barrel. The 100% budget load didn't disappoint and neither did this barrel.

Loaded up 42gr of this MP579 and shot a few groups before banging some steel. Out 50rd down the barrel

Here the first 5 shots down the barrel @ 100yd.

American Reloading MP579 (imr4451)
American Reloading New pulled Nosler primed brass
American Reloading 130 SMK pulls

I shot a few more groups @ 100yd before banging steel with the rest.

Would love to see how it does at distance 500-800 with the good components. I know I was super impressed with my 2 GM 22 barrels.

@BJG1979 you need to look into these

padom · Oct 11, 2024

I had some time today to size this 1x Norma brass. Used my LE Wilson SS FL Bushing die to bump shoulder 0.002 and squeeze necks down 0.004 under loaded. I then ran my 21st Century mandrel through them to give 0.002 neck tensuon.

I then ran them through the Henderson to trim to 1.91

Loaded up mini OCW 3rd each 43.1, 43.3, 43.5 and 43.7 with both MP579 (4451) tested previously and H4350.

I used Berger 130 Hybrids and 210M primers today seated 0.010 off lands.

The MP579 put up 2 impressive groups at 43.1gr and 43.5gr the barrel really liked.

H4350 shot like crap. I believe I'm a little too low on the charge for 130s... the equal charges compared between the H4350 rounds and the MP579 rounds... H4350 was 75fps slower. All else being equal..

I'm gonna load up some of these MP579 loads and test them a little further out...

padom · Oct 15, 2024

I got out today to do some pistol shooting and brought some 6.5cm rounds i loaded from the last test.. 43.5gr 130 Bergers

51F
2930 SD 4.4

I plugged the data into my Kestrel and updated environment and it spit out 2.0mils

I dialed 2mils and fired these 3 shots @ 500yds. They stacked on top each other in a 10mph wind. Measures 1.25" ctc. Looks like 2.1mil is dead center

I'd say this thing hammers. I then proceeded on to bang small swinger's at 630 and 700yd with boring consistency.

JR1200W3 · Oct 15, 2024

Truly Impressive

Earnhardt · Oct 15, 2024

Great thread man!

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Green Mountain 416SS 1.2" Centerfire Barrels Testing

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