The Brixia (Valtro) PM5 super thread!

[CDNsldr]

Ok, so explain this to the guy who got kicked out of metal work in the first week for making shuriken...

You're blobbing a bunch of weld on and then filing it to the correct shape once it hardens?

Yeah essentially. You could possibly run a continuous bead but I was afraid of burning through and I'm much too in-experienced to know the proper settings; so I ran a series of overlapping tacks (pulled the trigger for about 2 secs).

The second picture I just posted was just the start. You need to grossly oversize it if you want the corners to be square. In a few of the photos you can see where the material isn't quite high enough to form the corner...lol but whatever. I was tired of filing! Weld is a lot harder than mild steel so it takes a bit more effort to file.

You can start filing immediately. The time it takes to drop the mig gun and grab a file is plenty of time to "cool".

 

[JoKa]

One of my buddies suggested carrying these more horizontally in the small of your back. If I can figure out how to rig it, it sounds like that would be the most comfortable/most secure.

AirCAV thought about doing the same thing utilizing a paintball ammo holder. In the end he and I went with an over sized taco but we have not run a 30+ round shotgun stage yet.

I want to say his didnt think it would work because of the weight of the loaded mag. Its a heavy setup that would stretch it so there was not enough contact and the mag would just fall out. He might be able to speak up on that.

 

[JoKa]

Also, sorry I have not had time to send you close up pictures of mine. Been crazy lately. Even tonight I am spending my time packing for a PRS match tomorrow

SO THIS PICTURE shows what I wanted to warn you about. With mine, when I pushed the mag release catch...... If I let go of the catch just after the latch it would jam up on the back of the feed lips. So I needed to widen it a little bit to ensure a clean mag release EVERY time. I modified the picture to show you were I removed a bit of material in case you run into the same issue.

Might have to remove a bit of material a the top too but I am sure you can figure that out when doing final fitting.

 

[CDNsldr]

Also, sorry I have not had time to send you close up pictures of mine. Been crazy lately. Even tonight I am spending my time packing for a PRS match tomorrow

SO THIS PICTURE shows what I wanted to warn you about. With mine, when I pushed the mag release catch...... If I let go of the catch just after the latch it would jam up on the back of the feed lips. So I needed to widen it a little bit to ensure a clean mag release EVERY time. I modified the picture to show you were I removed a bit of material in case you run into the same issue.

Might have to remove a bit of material a the top too but I am sure you can figure that out when doing final fitting.

With the mag pouch thing, I think an extended taco would work if it could be mounted on a slight upward angle, especially if you can dial up the tension on the taco.

I can definitely see how the mag catch would get hung up in there. I haven't had a chance to run this latest mag through the shotgun as it's currently with the machinist. Still a bit more "cleaning up" to do.

 

[CDNsldr]

It was a good weekend! Shot my first ever 3Gun match at CHAS. Awesome group of people with a very relaxed, yet safe environment. My shotgun was still with the machinist, but there was another fellow (sorry, I don't remember your name! Please speak up if you surf this thread again) with a PM5 and a mounted EOTech who offered his shotgun for me to use during the shotgun stages! I ran the 2 11rd mags and 2 7rounders. Only issue with the SAP6 mags is the slight difference in design of the feed lips. They allow the front of the shell to flip up if you catch it on a pouch or something. Will try tweaking these by bending them in so they grab the shell more like the brixia mags do.

Other than that, once my drills get more proficient I should be well on my way to cleaning up the shotgun stages! I won one of the stages yesterday simply due to the speed of loading on an empty start.

I just got my shotgun back from my machinist buddy. Ill start off my saying he's a heavy industrial machinist with no experience gunsmithing, and he charged me a very small amount of $ considering what his time is worth. Having said that, I was a little disappointed with my milled Mesa Leo stock adaptor. I think part of the issue is Mesa, at some point, changed the design of the Mossberg 500 adaptor. The current Mossberg adapter appears to have some differences compared to the one Phat Eagle used for his PM5.

I didn't get any pics of the adapter straight from the machinist, but there was about a 3mm gap where it met the top of the receiver.

I spent today hand making a "shim plate" to help close the gap. It's nowhere near perfect as it was literally all done by hand filing.. buuuut it helps calm my slight bit of OCD...for now lol









If I had to do this stock adaptor mess over again, I would seriously look at the 870 adaptor as it's what Casey at TacOrd uses for the PM5. The angles are not friendly with the Mossberg adaptor.

 

[CDNsldr]

Also, let's talk about pistol grips! If you use a stock adaptor that is compatible with AR grips you are going to run into a slight dilemma. Normal A2 grips fit just fine, however they don't form a nice rounded transition for the webbing of your thumb.

The grip ends with a 90* corner to the buffer tube threads.


Now if you upgrade to one of the million aftermarket AR grips out there, most have a taller portion to form a nice nook for the webbing of your palm. You will need to trim this to that it will fit on this stock adaptor. I made the rough cut with a simple hack saw, then used a dremel and small milling bit to form the concave portion so it sat nicely against the rounded adaptor. This is the K2+ grip which is rubberized, so it was difficult to get clean edges.







Now there is a nice comfortable transition from the pistol grip to the stock adaptor!




Believe it or not, but the stock is actually slightly taller than the original Valtro butt stock as the Valtro stock has a funky step down. Gonna get magpul's tallest cheek riser then get my buddy to 3d print a completely new, taller one or just an extension to bolt onto the magpul riser if necessary.

 

[warrenlikesboats]

The 14" barrel had plenty enough pop at CHAS ?

 

[CDNsldr]

The 14" barrel had plenty enough pop at CHAS ?

On the particular stages they had set up I had zero issues knocking over the falling plates and poppers. They had vertical and horizontal spinners set up that I didn't have much issue with either...well no issues other that my individual ability hah.

Ammo choice and chokes could get you through anything!

 

[adriel]

Ahhh, now that I've read this thread, I understand the background story on those 11 round SAP6 mags you used over the weekend at CHAS.

 

[Phat Eagle]

I used a B5 P23 grip. It is less swept than the standard grip, and fits very well!

 

[CDNsldr]

I used a B5 P23 grip. It is less swept than the standard grip, and fits very well!

From the look of it, you had to trim it as well?

Thats exactly why I went with the K2+ grip, less sweep than standard grips. I use the K2 on my xcr and like it. Much more friendly to modern shooting stances.

 

[Phat Eagle]

Yes, it needed a little Xacto treatment...

 

[CDNsldr]

I cleaned up the two completed sap6 mags a bit and applied a couple quick coats of bluing. The bluing isn't pretty, but should keep corrosion at bay.
JoKa - As per what you mentioned, I cleaned up the rear of the feed lips to avoid the mag catch lever from jamming.

I also bent in the front of the feed lips a tad to hold the shell more securely. It's not an issue with high brass shells due to the small amount of extra diameter, but low brass target shells are still able to flip up. Will continue to tweak more.

Just gotta finish off the third mag now.

If anyone is interested in purchasing converted 11rd mags, I might be convinced to make a few more.. Money talks.

 

[CDNsldr]

I got the 3rd SAP6 mag finished and tweaked all three a bit more to hold the top shell more securely.

I also received some HSGI tacos (HCM and X2RP) and a magpul .75 cheek riser. The HCM tacos hold the 11rd mags perfectly, and the normal AR tacos will hold the 7rd mag. The .75 cheek riser is perfect.

My belt is starting to come together, just waiting for some back ordered tacos. Been practicing my drills and mag changes... Eventually I will be running the HCM tacos diagonally on the belt in my back, just gotta source (or build) a 45 degree PALS loop panel.

Video! ...gotta remember "slow is smooth, smooth is fast" when it comes to these rock n lock mag changes.

 

[warrenlikesboats]

I see your reloading Spetsnaz style... Very nice!

 

[CDNsldr]

I see your reloading Spetsnaz style... Very nice!

Experimenting with it anyways! It will take a bit of re-training to send the support hand directly to the new mag and not the mag release.

The way I see it is, with rock and lock style mags, you need to slow your hand down as you're inserting the new mag or else it's easy to fumble getting the front lug seated...hitting the mag release and flipping the old one out should accomplish just that.

Also need to train myself pull the pump back after last shell, as my support hand will already be moving rearward to get a fresh mag. Just seems like wasted movement if I don't utilize this.

Lot's more dry training to be had!

 

[CDNsldr]

Pulled a couple screen grabs from the video of the muzzle blast just for sh!ts n giggles

 

[CDNsldr]

Headed to the indoor 40m range this evening for a final test before 3gun this weekend.

Shot some 5 round groups to confirm my zero. Was getting around 3" groups. I think this is about on par for a shotgun, but I've never really seen an accuracy report for a short barrelled shotgun.




I'm sure the flyers were my doing, but Im relatively impressed with the "main" grouping size.





As well, I'm not sure of the general trajectory of slugs, so Im not overly sure what range to zero at. Currently I'm hitting about 2" high at 40m.

 

[wildphil24]

As well, I'm not sure of the general trajectory of slugs, so Im not overly sure what range to zero at. Currently I'm hitting about 2" high at 40m.

Last week I zeroed 2 12ga 18.5" with rifle sights.
Trajectory was similar with Rem Slugger 7/8oz high velocity and S&B special sport 1oz.
With a 100m zero I got +8" at 60m and -24-36" at 150m.
So I'd guess your zero is between 50-70m.

Thanks for your time in this nice thread.

 

[CDNsldr]

So this happened today...










Jeff at Grizzly Gunworks in Ontario makes these. He duplicated the threads perfectly. This brake is suppose to offer a 60% recoil reduction. Can't wait to test it!


...and yes, I fully realize how obnoxiously overdone/overkill this brake is....exact reason why I bought it