2K9 Mag Velocity Discoveries

[Memornix]

Awhile back I bought a lot of 2k9 mags from Woouulf with the intention of digging into the "so called" velocity issues. Well, Today is finally the day to dig in.

I have built up 2 of them both with X-valves (will test classic valves also)





So far, I have found 2 things:

1st, the barrels are huge and with the stock barrel, max velocity is about 250-265fps. With a properly sized barrel, 300fps is doable.

2nd, there are dimensional differences between these and a standard MiniMag. In the image below, you will see the seat for the spring and the feed tube are different dimensions from the back of the body and that the mini mag has a little lip inside to center the spring



I doubt I can easily do anything about the feed tube location, but I can modify the spring seat to closer match the MiniMag.

Off to the lathe and will report back with before and after velocity tests.

[Memornix]

Back from the lathe and here are the results:



I used the same valve, barrel, tank, etc. and didn't change anything but machining the spring seat as shown above. I took 3 shoots pre machining and got 270, 271, 277. After machining, I saw 305, 304, 301.

I am going to check how much room I have left and see if I can take it deeper then make a steel insert to prevent the aluminum from mushrooming from the spring/bolt impact which also has been a reported issue.

[Memornix]

I made a stainless ring, took the bodies down a little more and still have about 305fps with the ring installed. Here's a pic of the where i had to take down the inside of the body and the ring I made. The inside of the body isn't as smooth as I would prefer but the boring bar was pretty long.





I am going to consider this one good and move on to another and see if I can replicate the results.

[Memornix]

Shooting video (sorry for the loud mouth breathing, fighting a cold and can't use my nose right now):

for the last shot I cranked it to max.

https://youtube.com/shorts/BUhXoTkfJ...fbbiagkGxwQCTA

[Memornix]

reserved for possibly even more content

[dano_____]

My old body came close to 275 without the steel cup, but the spring would eat the hell out of the body without it. I never got above 250 with the cup in place.

[Memornix]

yep, looks like the cup pushes the spring too far back so I had to cut to correct for that.

[Trbo323]

Subscribing. This is great content.

A while ago this topic came up in another thread and Luke knew what caused it but refused to tell the people in the thread. It would be one thing if he was fixing it as a service but he said he is no longer doing that.

I'm glad someone still values releasing information like this.

Sent from my motorola edge 5G UW (2021) using Tapatalk

[Hellion360]

If this process is proven and becomes available I have a body that I would send in.

[superman]

This is pretty similar to what i was expecting. Are you measuring from the back for the rail to the spring seat on the minimag? If so you may want to measure from the field strip screw hole. the am/mm rails are saw cut, but i forget if it is saw cut on both ends or not.

When i measured and made a post about this in the past it looked like it was about 1/8" difference between the mm2k9 body and a ule body. I measured mine using the same spring and bolt between the 2 and pressing it to full compression and marking through the breach.

Sounds like to full correct it, it would require making a new breach.

[Memornix]

This is pretty similar to what i was expecting. Are you measuring from the back for the rail to the spring seat on the minimag? If so you may want to measure from the field strip screw hole. the am/mm rails are saw cut, but i forget if it is saw cut on both ends or not.

When i measured and made a post about this in the past it looked like it was about 1/8" difference between the mm2k9 body and a ule body. I measured mine using the same spring and bolt between the 2 and pressing it to full compression and marking through the breach.

Sounds like to full correct it, it would require making a new breach.

I was measuring from the back of body where the valve seats in on both. Seems like there is the about the same gap on both my minimag and the 2k9 bodies.

After doing 2 of these bodies today, it seems like they are inconsistent at best. One needed about .090" taken off to work with the stainless ring and the other needed about .150"

I am not sure how much the breach placement is effecting the velocity, but you are correct, I am seeing about .100" difference.

[russc]

That's a massive difference on a machined part. Crazy.

[Trbo323]

What would happen if you take that .1 out of the spring itself?

what about the bolt where the spring sits?

Sent from my motorola edge 5G UW (2021) using Tapatalk

[Memornix]

What would happen if you take that .1 out of the spring itself?

what about the bolt where the spring sits?

Sent from my motorola edge 5G UW (2021) using Tapatalk

Taking it off the flange on the bolt would probably solve the velocity issue but it would make it sit too far forward when it is in the back position. Not sure how you take it off the spring of if that will still let the bolt get all the way forward.

Taking it off the body also keeps bolt/spring replacement easy.

[FredMnkyDad10]

This is pretty similar to what i was expecting. Are you measuring from the back for the rail to the spring seat on the minimag? If so you may want to measure from the field strip screw hole. the am/mm rails are saw cut, but i forget if it is saw cut on both ends or not.

When i measured and made a post about this in the past it looked like it was about 1/8" difference between the mm2k9 body and a ule body. I measured mine using the same spring and bolt between the 2 and pressing it to full compression and marking through the breach.

Sounds like to full correct it, it would require making a new breach.

Luke was able to correct the issue without doing a new breach. He had done I think two for testing prior to offering the service to the rest.

I was going to send mine to have the milling done, but life and things got in the way. By the time I came back he had stopped doing the service long ago.

For sure subscribing. Hope it works and I can send the two bodies I have. Keep up the great work.

[superman]

Measured the 4 of my bodies from the valve rest to the spring rest (no stainless cup) 2.975- 2.985".
Measured using calipers so it only gets so close/accurate, but i think you are on to it for sure.

[Olsson]

As an Automag fanboy, I wholeheartedly salute you for your tribulations, sir.

The velocities you're quoting, is that with lvl 7 or lvl 10?