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  1. #1
    Member AbHobbyist's Avatar
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    Jun 2012

    AbH's MRA Renegade Straight pull Bolt-Action Build and Load Development Thread

    Hello there to all the members of GOC!!

    May 1, 2020 was a very dark day for the firearms community with the effective banning of the AR-15 through order in council. As a result many of us ended up with very expensive builds we could no longer take to the range or use, however through adversity the light of ingenuity and innovation can shine.

    Enter Canadian manufacture and fabricator Maple Ridge Armory with the Renegade Receiver set. For those of you that are not familiar, this is set that is actually a straight pull manual bolt action with spring assist, that will take/use the majority of AR-15 parts, magazines and be none-restricted as long as its overall length is greater that 660mm.

    MRA was not the only one, but to-date they are the company, that at this time, and in my opinion have the best quality product and design with most of the features I am looking for. The Renegade has suffered some teething issues, but nothing at this point that is not insurmountable.

    Like, love it, or leave it, with the current legal political and legal climate that exits in Canada for AR-15 owners, the Renegade is one of the best options to put AR parts to use and legally be able to shoot them.

    With that in mind I thought I might share my experiences in working with and developing loads for my personal MRA Renegade build.

    Before we proceed the following are just my thoughts and experiences working with the above mentioned. You may or may not agree with what I have to say, and I welcome comments and criticisms as long as the shared in a constructive well though out manor. With that out of the way lets proceed.............

    Installment #1 - Upper Assembly

    We will start with a few glamor shot of the receiver set and associated kit


    The first thing to consider was what caliber? I wanted something a little different, but still could be supported with my own established supply chain. I have always been fascinate with the 300 ACC Black out. Though originally used in short barreled AR-15 carbines by ERT door kickers, it is my understanding that it is becoming more poplar/useful in an urban environment in the role of over-watch or DMR in longer barreled accurate carbines where engagement distances are 300m and under. I have always wanted to test the accuracy of the 300 Black and thought this would be a perfect opportunity to do so. Further at this point, as we are not allowed by law to use sound suppressers Canada, I will be concentrating on the use of Super-Sonic ammunition which I will reload myself.

    Barrels and Barrel length:

    A quick glance through my parts bin and I turned up with these two barrels

    The top is a Green Mountain 16" 300 black out barrel (chrome lined, 1-7 twist)
    The bottom one is a 10.5" Faxon Barrel, (Nitride finish, 1-8 twist)

    Both barrels are new, have had the bore well scrubbed and treated with Microlon Gun-Juice.

    If one searches the internet on 300 black and barrel length one will invariably stumble across the following chart:

    Please note: in order to give proper reference the above chart was taken from Fenix Ammunition's Article - A Ballistic Comparison of 5.56x45mm vs. .300 AAC Blackout

    If memory serves, with super sonic 110 grain ammo, this chart shows that the sweet spot is around 10-11" where one gains about 50 + fps for every inch of barrel gained prior to that point. After that, one gains 20-30 fps for every inch until about 16", and that seems to me to be the point of diminishing returns. As I wanted to test the full accuracy potential of supper sonic ammo, I have decided to to go with the 16" barrel.

    Free float tube of Rail

    I have always been a fan of old school quad-rails in some circles as “Cheese Graters”. I had been holding back the following 14: Troy MRF rail in FDE

    However when I wen to install it, there was not enough clearance in order for the receiver and free-float tube top rails to align (the free float tube rail was about 1/8" to high). I tired two more rails and finally settled on the one piece Mid-West Industries 10" M-Lok compatible rail from their Suppressor Compatible line with its one proprietary barrel nut. Its claim to fame is its generous internal dimension specifically to accommodate sound suppressers.

    Gas Block or Gas Stop

    The MRA Renegade has no gas system (the action is manual) and as such if your barrel has a gas port it must be block on some fashion. The receiver set does come with a shaved down gas stop, however gen 1 users have found that with certain calibers its failing and breaking apart. As such I opted for a 4140 steel gas block with a parker-ized finish from a Canadian supplier mounted in reverse to act as my gas stop.


    I was able to finally spend some time at the work bench last night, and this is the progress to date:

    There will be lots more decision and work to come, but this is what I have to share to this point.

    Thank you for your time and I look forward to all your constructive comments.

    Warmest regards

    Last edited by AbHobbyist; 10-15-2020 at 01:50 PM. Reason: Velocity vs barrel length chart added

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  3. #2
    Member AbHobbyist's Avatar
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    Jun 2012
    Spot Reserved for Installment #1 - Upper Assembly (Continued)

    Installment #1 - Upper Assembly (Continued)

    Bolt, Carrier, and Charging Handle Group:

    Now that we have the bones of the upper together it was time to move onto the MRA Bolt assembly. Now the kit comes with its own charging hand/bolt carrier you will need to provide your own Bolt group, firing pin cam pin and cotter pin.

    As AAC were the inventor of the 300 Blackout cartrigde I thought it appropriate to use the parts needed from one of there manufactured bolt & Carrier groups. This is what it looks like:

    Don’t mind the grease and oil. This is what is looks like broken down into its component parts

    Here are the AAC and MRA component parts side-by-side

    This is what it looks like assembled

    As you can see the charging handle is similar to the one use in the JR carbine in that it a “T” handle style attached to the bolt carrier. Over all the assembly went together very well, as long as you follow the well illustrated Instruction manual from Mapple Ridge Arms. The only foibles were:

    -If you are using a complete AR-15 BCG MAKE SURE that you remove the gas rings, as the rifle will not function properly with them!!

    -The dowel pin holes needed to be cleared of tumbling media

    -I had to use a a different cotter pin as the one that came with the AAC bcg was a poor fit.

    -When installing the charging handle dowel pins I used a little blue loctite on the end that slid into the handle just to make sure they did not get lost should the CH come off in the field under some failure

    None of the above mentioned were a big deal as I had spare cotter pins, pipe cleaners and blue loc-tite on hand.

    Note: In my travel I stumbled across an AR-15 upper vice block specifically for cleaning. It looks as follows:

    While it is not necessary, I found it very helpful when working on installing the MRA BCG/CH group as it held the upper solidly in place while allowing free access to the BCG race way

    Stock Assembly choices

    Yes that is correct, when assembling the MRA upper you will need to think about stocks as the buffer tube is attached to the upper.

    As I am building a “Precision Short rifle” I thought it appropriate to use a Magpul PRS with some enhancements:

    However it turns out that the Renegade is currently configured for carbine buffer tubes only!! I was none to pleased about this, and said as to MRA directly in their thread. MRA responded that this was an oversight in design, that there were working on an adapter plate to take fixed stocks, and hoped to have it available some time in November 2020.

    That is all fine and good, but that does not help me NOW!! So I started thinking about precision stock choices that used a carbine buffer tube. The Ruger Precision Rifle Stock came to mind, and they look like this:

    Now some of you may remember my post Project: Will an Ruger Precision Rifle stock work on an AR-15 (Click the link if you would like to see that post)

    I happen to have one in the bin. I removed the standard end plate the RPR stock came with and replaced it with the MRA proprietary one, added a quality standard carbine buffer and spring and installed it on the Renegade upper receiver.

    Once done, using the above mentioned vice block, the project looked like this:

    Obligatory Progress glamor shots

    The following are a couple of glamor shots of progress to-date:

    Muzzle Treatment

    When considering a muzzle treatment, 300 Blackout is not really known for its heavy recoil or its muzzle flip. On the contrary its actually a pleasant cartridge to shoot, with more of a push and the muzzle rise is quite easy to control.

    I spend a good amount of time shooting indoors and wanted something that would send what muzzle report there was down range and away from the shooting line.

    With that in mind, I thought a linear comp would fit the bill. Further I was not that pleased with the aesthetes of that much barrel in front of a 10" rail.

    Fortunately True North Arms offers a shroud or Revers style “fake sound suppresser” with a linear break component. The shroud portion covers about 4" of barrel, and the linear comp portion adds about 1" of length. Further this latest version of this unit has a subtle laser engraving with the bore diameter and thread specs for easy identification. Perfect!! This is what I needed.

    To be clear this muzzle treatment works like as follows:

    Further it arrived this morning. It looks like this:

    When installing any muzzle treatment it's a good idea to use some anti-seize compound, and you don't need much.

    To make its application easier and less messy, I have put some in a grease syringe and apply it as follows:

    One quirk of this muzzle treatment is that there is not enough room for a 5/8 crush washer as illistrated about. For now I have spun it on and gave it a good turn with a strap wrench.

    Should this not be sufficient, I will look as getting the the appropriate Hight-Temp O-ring.

    Installed the treatment looks like this:

    Over all I am very pleased with the results!!

    Well that is it for now, I look forward to adding an optic/mount package and completing the lower!!

    Thanks for taking the time to read my post, and I will do my best to field any comments or questions you have.


    Last edited by AbHobbyist; 12-30-2020 at 04:02 PM. Reason: BCG/CH & Muzzle treatment pic's updated

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  5. #3
    Member AbHobbyist's Avatar
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    Jun 2012
    Spot Reserved for Installment #2

    Lower Assembly

    For the most part the assembly of the lower was straight forward, but there were a few foibles to note:

    -The pivot and take down pins are actually larger/thicker than AR-15 pins so you will have to use the ones provided and will not be able to use after market “Easy Grip” ones

    -The front pivot pin detent race way was full of tumble media. I removed it by take the appropriate size drill bit and spinning it with my fingers to clean it out.

    - The dimensions in the fire control pocket are ever so slightly different and I was unable to use the Elftman Trigger that I wanted to. I did end up using my LMT Tactical trigger

    -There was some play between the upper an lower, however there is a provision for a nylon-tipped tensioning screw. The lower does not come with one, and I am currently trying to source these, but for now I borrowed one from an Aero Precision lower of mine.

    Further while not required one of the additional things I like to do is tape the rear take down pin detent race way for a grub screw so that the rear take down pin assembly is captured. When you do this you will also need to cut a few coils of the detent spring.

    Here we are taping the race

    The tap is now complete and the chips have been cleaned away with a squeeze of rubbing alcohol from a pointed syringe followed by a blast of compressed air (note: the installed lower to upper tensioning screw)

    When installing the grub screw under tension it really helps to have the correct driver!!

    Top view of nearly completed lower with Ambi-Selector, LMT tactical fire control group, and a Norgon Ambi-Mag release.

    Optics, mount

    For an optic, I wanted something that would have enough magnification to shoot at distance, be clear, and have enough reticle flexibility to allow for hold-overs, and still fit in the budget.

    While some of you might find it a funny choice I settled on the Cabela's Covenant Tactical SFP Rifles cope in the 4-16 x 44 Variety with a 30mm main body. This optic is very good quality for the $’s spent, has repeatable tactile turrets, and has the TAC 32 reticle, which looks like this:

    As for the mount, I wanted something was quality, could easily be removed or swapped, allowed for use of a large main body if require and had 20 MOA cant in it, and was smooth sided (so that you whack your knuckles on any the mount protrusions while actuating the charging handle!!). I settled on a Desert Tech HD Ultralight Scope Mount. The mount is actual meant for optics with a 34 mm main body, but came with the heaviest duty ring reduces/adapters I have every seen. Just in case I also added a Wheeler Anti-Cant Device. All put together it looks like this.

    Brass Catcher:

    For auto loaders I think a brass catcher is “Must have” addition to the rifle. For a straight pull bolt gun I think its not a bad Idea either, especially if I want to keep track of carefully prep'd brass. I am fond of the 3bucc brass catcher, they are light, easy to remove, and generally just work well. All it takes is an adapter mounted to ones top rail (you can see it in the above picture). With the catcher installed it looks like this:

    ..... And finally here are a couple Obligatory Glamor Shots of the completed project

    Well that is it for now.

    The next step is live fire test and load development.

    Thanks for making time to read my post and I look forward to any constructive thoughts or comments you might have


    Last edited by AbHobbyist; 10-19-2020 at 11:22 AM. Reason: Added Optic, mount & Brass catcher info

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  7. #4
    Canadian ForcesOgre Haywire1's Avatar
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    Jun 2012
    Man thats turning out nice!
    More, more!
    in pace, ut sapiens, aptarit idonea bello
    - In peace, like a wise man, he appropriately prepares for war

  8. #5
    Senior Member stevebc's Avatar
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    May 2012
    Wouldn't this be just another "variant"?
    "When government grows, freedom shrinks." - US Senate candidate for Alaska, Kelly Tshibaka.

  9. #6
    Member AbHobbyist's Avatar
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    Jun 2012
    Quote Originally Posted by stevebc View Post
    Wouldn't this be just another "variant"?
    Respectfully it is not. The following quote is from the manufacturer on another site:

    Quote Originally Posted by Maple Ridge Armourer
    The MRA Renegade Receiver Set is a novel, spring assisted, straight pull, magazine fed firearm design.

    # It is composed of a proprietary Receiver, Bottom Metal, and proprietary bolt carrier with integrated, swap-able left or right hand charging handle.

    # This receiver kit is compatible with a wide variety of commonly available firearm parts and accessories.

    # In this way, the user can build a rifle to meet their specific utility and budget.

    # This receiver set is designed and intended to not be capable of discharging ammunition in a semi-automatic fashion.

    # The design is novel and is not derived from any restricted or prohibited firearm.

    # Due to the action type and novel design, this receiver set meets the legal standard of a non-restricted firearm as per the Canadian Firearms Act and related Regulations.

    # The minimum overall length when assembled into a working firearm must be over 26" to meet the standard of non-restricted.
    As you can see it is a new and novel design (the manufactures words) that will not accept an AR-15 upper or lower.

    My observations from working with this are as follows:

    - Renegade Carrier is actually at least 0.020" smaller, requires a special torque/reaction rod and will not accept an AR-15 carrier.

    - The bolt key is a proprietary low profile design and There is no clearance for a standard AR-15 bolt key and there is no prevision for a gas system

    - As you will see shortly the buffer tube is attached to the upper in the style of a JR carbine

    So in short, No its not a variant, and the manufacture has assured the consumer that any such assertion by any body or agency will be met with swift legal counter action.

    As such I felt comfortable proceeding with projects on this platform based on my research.

    Further I would encourage you do to your own research.

    I hope you found this helpful.



  10. #7
    Canadian ForcesOgre Haywire1's Avatar
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    Jun 2012
    Thats turning out beautiful
    in pace, ut sapiens, aptarit idonea bello
    - In peace, like a wise man, he appropriately prepares for war

  11. #8
    Member AbHobbyist's Avatar
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    Jun 2012
    Post 1 updated with muzzle treatment!!



  12. #9
    Senior Member
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    Feb 2013
    How does the bolt come out of the upper if the stock is attached at the back?

    FWIW 300 Black is much better in short barrels typically in the 8-10" range. I have ARs in 7", 10" and 12" configurations. The 7" is really fun to shoot because it is so small and gives up basically nothing in terms of ballistic performance with subsonics.

  13. #10
    Member AbHobbyist's Avatar
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    Jun 2012

    Thx for stopping by and taking the time to read my Thread.

    You pose a good question. To my mind the MRA Renegade seems to take many ques from and is similar in several ways to the JR Carbine.

    To remove the BCG/CH group from the upper receiver one must:

    a) remove the entire stock assembly (this includes the buffer and spring assembly)

    b) then remove the bolt side charging handle

    c) the slide out the BCG assembly.

    A more detailed look can be had here MRA Owners & Assembly Manual (Click the link if you would like to see the manual)

    I will agree it is not the most efficient set up, however as this is a manual action and there is NO direct impingement of Blow back gases in action area (with the bolt remaining closed until manually actuated) The combustion and its associated residues should be kept contained to the chamber keeping the action much cleaner and clear for a longer period of use.

    As for barrel length..........

    I will defer to your greater experience working with Sub-Sonic ammunition using pistol and other powders like trail boss underneath very heavy for caliber projectiles (175-200+ grains). I can logically see where there is a real advantage to shorter barrels and how a dedicated build to shooting sub-sonic's should have one. The only caveat being that over-all length must meet the 660mm ~ 26" requirement.

    However the purpose for my build is to shoot mainly super sonic ammunition with powders like CFE-Black and H-110 under lighter projectiles (110 - 150 grains) out to medium distances. The research I have done on the powders I plan to use is that in 16" of barrel the majority of the powder charge is consumed giving optimal performance. Further research has shown anything longer than 16 inches is actually detrimental to ballistic performance (giving credence to your rule of thumb that shorter is better - for the 300 blackout)

    A really interesting demonstration would be to build a short (ie 10.5") and a longer (ie 16.1") build. Then feed them both exactly the same demo ammunition of both Super-Sonic and Sub-Sonic, and see how they preformed where each build excelled and faltered. However there are only so many resources to go around, and I myself will have to concentrate on one build at the time.

    Perhaps you have some experiences to share in this area, and I look forward to it as it would make a great precursor discussion to Load development.



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