CMT 308 is Ready

[gatordev]

After building and using about 15 different .308 platforms I came to the conclusion that even Slash's carbine .308 heavy buffers are a band aid and will never run as well as a rifle length extension set up. If the carbine extension is a must then a CAR-10 XH buffer with a Sprinco orange spring has proven to be the best choice for me. I saw 0 difference between a A5 with a XH buffer (A5 extensions can use a standard AR15 length buffer even with .308's) with one of Slash's springs and the standard AR15 tube with a Sprinco orange spring. Also I am not a fan of the springs he sells. When I see surface rust on a spring less than a month old I tend to suspect the quality of the spring immediately.

Between Sinner's and Slipper's input when I was having issues, I went through both Slash configs and then A5 configs. I can't comment on spring corrosion (though I'll go look), but at the end of the day, none of the various setups fixed the overall issue of over-gassing, as Sinner is saying. Even with the A5, shooting this barrel was "stout." Put a suppressor on it and it was downright domestic violence. At the end of the day, throwing more money at the problem and buying the Gemtech carrier made the system much friendlier, but it just irked me that that had to be the solution.

[Big_Tom]

Between Sinner's and Slipper's input when I was having issues, I went through both Slash configs and then A5 configs. I can't comment on spring corrosion (though I'll go look), but at the end of the day, none of the various setups fixed the overall issue of over-gassing, as Sinner is saying. Even with the A5, shooting this barrel was "stout." Put a suppressor on it and it was downright domestic violence. At the end of the day, throwing more money at the problem and buying the Gemtech carrier made the system much friendlier, but it just irked me that that had to be the solution.

I don't think there are many 308 ARs out there that aren't overgassed. It's almost hereditary. I see and hear about it all the time. Installing adjustable gas systems is best way to take care of it.

[gatordev]

I don't think there are many 308 ARs out there that aren't overgassed. It's almost hereditary. I see and hear about it all the time. Installing adjustable gas systems is best way to take care of it.

That answer is a cop out to me. I understand why manufacturers over-gas their barrels, but it still drives me crazy. Build it to the NATO spec. But then Joe-Bob buys cheap, weak ammo and the upper doesn't run! Well, then many 308 isn't for you...

But this is an argument/discussion that's been had here before. For me, I'm shooting spec or near spec ammo, so I'd prefer a gas port that matches that. I also don't want to have to deal with an adjustable gas block, no matter how good and how well it's supposed to hold the setting. It would just be nice to have manufacturers specify what they've built their product to support. Sadly, this was not the case with my Rainier barrel and it ended up costing me more money to get it to a point where it ran reliably when I could have just gone with another barrel from the beginning.

[fledge]

It would just be nice to have manufacturers specify what they've built their product to support.

I wish they would at least specify the ammo they use for testing. For not even all quality ammo has the same pressure. My SPR will not cycle Magtech 77gr. It will cycle 55gr federal bulk Walmart ammo without issue. Go figure.

[Big_Tom]

That answer is a cop out to me. I understand why manufacturers over-gas their barrels, but it still drives me crazy. Build it to the NATO spec. But then Joe-Bob buys cheap, weak ammo and the upper doesn't run! Well, then many 308 isn't for you...

But this is an argument/discussion that's been had here before. For me, I'm shooting spec or near spec ammo, so I'd prefer a gas port that matches that. I also don't want to have to deal with an adjustable gas block, no matter how good and how well it's supposed to hold the setting. It would just be nice to have manufacturers specify what they've built their product to support. Sadly, this was not the case with my Rainier barrel and it ended up costing me more money to get it to a point where it ran reliably when I could have just gone with another barrel from the beginning.

You are exactly right. They the manufacturers need to do more research but that cost money and time. And I should have put it's a remedy for the issue but not the correct fix. Adjustable gas systems should've there if you want really fine tune the system not to fix the issue.

[SINNER]

Good video of the different tubes and stock compatibility.

https://m.youtube.com/watch?v=UnrVJT4UU10

[SINNER]

Funny because I live about 500' from the Chesapeake bay and I've never seen a spot of rust on a Sprinco spring. I have been lightly greasing all my springs for years now so that may be why.

The spring I got from Heavybuffers was actually rusted so much I could see it under the stock when it was extended. Rust particles were coming out of the relief hole.

[Slippers]

Funny because I live about 500' from the Chesapeake bay and I've never seen a spot of rust on a Sprinco spring. I have been lightly greasing all my springs for years now so that may be why.

The spring I got from Heavybuffers was actually rusted so much I could see it under the stock when it was extended. Rust particles were coming out of the relief hole.

Someone asked me why I don't like them, and I answered. I'm not giving anyone grief for using them, but I personally don't like them. If you're happy with sprinco, cool.

[SINNER]

Not questioning your experience or preference at all. Just stating mine because it was different.

[Joelski]

I pulled my JP springs out the other day and they're just as shiny as they were when new. What is this rust issue you speak of?

[gatordev]

Wurd.

[Pyzik]

Thanks Uwone for the deal on the scope and Mustangfreek for the PIF on the mount. Just sitting on the rifle for a quick pic. Still think I might need to paint the scope.

Should be able to hit the range this weekend or next week.


Scoped by Damage Photos, on Flickr

[Dstrbdmedic167]

Looks great as is!


Sent from my iPhone using Tapatalk

[Joelski]

Indeed.

[Big_Tom]

Really makes me want to get broker than I am already and buy a scope for mine. I hate Ramon Noodles.