Maple Ridge Armoury AR10 Barrels. Shot targets added post #75 Nov 16th

Epoxy7 said:
And.. International barrels initially told me no when I emailed asking for a barrel with the above specs.. :ninja: Glad to see you guys providing a barrel with true 308 military precision rifle specs. Thank you!

If you want to tighten those groups up give 175 smk with 43.4 of varget or 44 grains of varget a try. The Federal Gold 175 is a bit slow and with the 18.6" length you're likely just a bit slow to hit the optimum accuracy. The 20" version will likely correct that for off the shelf match ammo while still shooting the above formula like a laser.

Waiting for the 20" version SPR....
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Even with the 1:11.25 twist rate? What about shooting something lighter like a 168gr proj ?
 
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Bonjour43ma said:
Even with the 1:11.25 twist rate? What about shooting something lighter like a 168gr proj ?
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Yes I68 is a better bet for off the shelf match ammo due to FPS and the accuracy node . As is 167 Lapua. For reloads I use the same varget formula for both 168 and 175. Also I’ve had excellent results with 155 using this twist rate but in a longer barrel.

I suspect the reason the shown groups on this thread were as good as they were in that 18.6" barrel is due to a few combinations but predominantly the 5R rifling which does tend to give better velocity vs a non 5R rifled barrel. The twist rate is optimized for 167-178 rounds. The M118LR chamber is also excellent for these rounds. When they announced this project it's why I asked for those specs. When the KAC SR25 won the M110 contract they were actually using Remington 5R barrels and in 20". When you buy a LMT MWS 20" barrel it's also 1:11.25 twist as was the Canadian military AR10t with it's 24" barrel. These specs have been used for AR10/AR308 rifles in military applications since early 2000. Read up on the success that Remington 5R milspec owners have had which have this twist rate and have barrels based on recountoured M24 barrels.

Keep in mind that most off the shelf match ammo with Federal Gold being the standard are for a 20-26” barrel. With an 18.6” barrel some tweaking might be required. Federal gold is the civilian version of the Military round and military rifles are predominantly 1:11.25 twist rates.

A Federal gold clone round load is 43 grains of varget with 168 or 175 SMK bullet. A bit hotter at 43.4 or even 44 seems to be the ticket. I find it shoots a bit tighter even in guns that love Federal gold.

The results posted with these barrels at 18.6” and with 175 Federal off the shelf match ammo are exactly what I would expect, which is a good thing. They should be fairly easy to really dial in. Even easier in the 20” version which I’m waiting for.
Also I would suspect that 168 Federal Gold off the shelf match ammo might be even tighter shooting than that 175 Federal.
 
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Here's an interesting video on Faxon's pencil barrel. Supposedly with "proper stress relief"

Would your pencil barrels be similar to that claim?
 
Bonjour43ma said:
Here's an interesting video on Faxon's pencil barrel. Supposedly with "proper stress relief"

Would your pencil barrels be similar to that claim?
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Interesting. The IBI blanks are properly stress relieved. We will run a test similar to this and post the results here.

For the 308 Pencil barrels we will burn 20 rounds between 5 shot groups. This should be sufficient to heat up the barrel since the wall thickness is similar to that of the 223 barrels but there is greater pressure and heat from the round. For the 223 Pencil barrels, we will do a 30 round dump as in this video.

Stay tuned!
 
Wow looking forward to it! I'm still undecided between the .308 SPR or the pencil and your test will be awesome to help make that decision.
 
Finally received mine. Won't get a chance to shoot it until after the new year when the rest of my parts arrive from the US, so the only thing I can do is look at it.

Which leads me to notice this: while the barrel index pin and gas port are aligned with each other, they are misaligned with the fluting on the barrel. The asymmetry is unfortunate from an aesthetics standpoint. Not sure if there are any implications as to barrel harmonics.

KL0QVaJ.jpg
FN9fPTT.jpg
 
I should ask if the nitride process for the barrels is SAE standard AMS-2753? Also any issues with the heat of the process and the temper (heat stressing) of the barrel blanks?
 
RKRZ said:
Finally received mine. Won't get a chance to shoot it until after the new year when the rest of my parts arrive from the US, so the only thing I can do is look at it.

Which leads me to notice this: while the barrel index pin and gas port are aligned with each other, they are misaligned with the fluting on the barrel. The asymmetry is unfortunate from an aesthetics standpoint. Not sure if there are any implications as to barrel harmonics.

KL0QVaJ.jpg
FN9fPTT.jpg
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That would drive my OCD crazy.
 
jiffx2781 said:
That would drive my OCD crazy.
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We cannot perfectly time the chamber threads of the barrel in relation to the flutes. In this way, we cannot determine where the barrel extension will bottom out and in turn where the index pin will align. The gas port is drilled as the final step in production and is located off the barrel extension index pin. For this reason, we are unable to symmetrically time the gas port to the flutes.

Trust me, if there was an easy way to align the flutes with the gas port, then we would be doing this. If anyone has any ideas on how we can easily do this for mass production, I am all ears.
 
Epoxy7 said:
I should ask if the nitride process for the barrels is SAE standard AMS-2753? Also any issues with the heat of the process and the temper (heat stressing) of the barrel blanks?
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Yes we nitride to SAE standard AMS-2753C. I will gladly email a QPQ Certificate and lab report.

For that matter, we anodize to Mil-A-8625 and we have certificates of conformity for this also.

Email the request to info@mapleridgearmoury.com
 
Maple Ridge Armourer said:
If anyone has any ideas on how we can easily do this for mass production, I am all ears.
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Not sure about my idea but just in case... Could you rotate the flutes 45 degrees? As the flutes are wider (than the ridges/ribs) it could be harder to locate their center. Possibly giving a few more degrees of forgiveness before the eye catches the imperfection.

Beautiful handguard as well.
 
Maple Ridge Armourer said:
We cannot perfectly time the chamber threads of the barrel in relation to the flutes. In this way, we cannot determine where the barrel extension will bottom out and in turn where the index pin will align. The gas port is drilled as the final step in production and is located off the barrel extension index pin. For this reason, we are unable to symmetrically time the gas port to the flutes.

Trust me, if there was an easy way to align the flutes with the gas port, then we would be doing this. If anyone has any ideas on how we can easily do this for mass production, I am all ears.
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Mill the flutes after its indexed is about the only way to get them perfect everytime. Or just dont flute them if that's possible. Wish you offered them without flutes
 
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