The LARPV

**Scott Evans** · 07-16-2011, 05:18 PM

LRPV, Pac-Nor 20 Practical, 11 tw, modified for AR15 mags. Feed is about 95% with untouched Brownell's 20 or 30 round mags, am going to probably have to tweak the mags a little to get to 99%.

Oh, and the CO2 phase change cooling system.

We don't stop for hot barrels

**pdog06** · 07-16-2011, 05:48 PM

now that is sweet!!!

Can use give us some more pics of the DBM mod setup?

**Scott Evans** · 07-16-2011, 05:57 PM

Wouldn't call it a DBM, people would think those are Savage mags, they are unmodified (so far) std AR15 mags.

Some pics earlier in the process are at http://s163.photobucket.com/albums/t313/GrocMax/LARPV/

Took a few tries tweaking things to get consistent feed w/o scraping/jamming cases, of course.

Mag latch is a little 'crude', had to go with a design that was adjustable in height after epoxying the assembly in, and I could do the machining with what I have available. Don't really care, reality of the situation this is a truck gun that gets beat up a bit and kills a LOT of PD's. Mag HAS to sit in the right spot for feed to work good, better setup would be to lower mag slightly and put two pins on bottom of bolt head for case rims to catch on, but you'd need to broach two slots into the bottom of the receiver, and I don't have a broach. Or know anyone who has one

. I'm going to guess that an AR10 mag would work better actually.

2nd time around will be doing things quite a bit different, but its functional. PD partner saw me cycle 30 rds thru in about 15 seconds and has made a request for one.

Martin · 07-19-2011, 02:57 AM

I like the cooling bottle. Tell us about it. How you fixed it up.
Martin

**Scott Evans** · 07-19-2011, 03:11 PM

Originally Posted by Martin

I like the cooling bottle. Tell us about it. How you fixed it up.
Martin

Regular old phase change cooling, liquid CO2 thru a .010" orifice stuck in the breech, as it turns to gas it has to absorb heat from the surrounding area, just like your A/C. As long as you don't cool it below the current dewpoint you won't get any condensation or ice.

Coyotejunki · 11-20-2011, 11:57 AM

How does that work on the bench? Do the mags get in the way?

**henry1** · 11-23-2011, 02:34 PM

Interesting cooling system, how do you make sure that you dont get condensation in there, just feel like there is a lot of variable there....what if?
H.

**henry1** · 11-23-2011, 02:35 PM

Also would be curious as to how .223 AI would feed out of the AR mag....

shaman · 11-27-2011, 08:22 AM

Will you be doing this for other people, the mags, not the CO2

**sha-ul** · 12-29-2011, 02:59 AM

I have been looking for something like this for my 223& 300 WTF.

**Scott Evans** · 01-29-2012, 08:54 PM

Sorry haven't been here in awhile.

No, I wouldn't do this for anybody but me, its more of a 'yes it can be done' deal.

Range report; Last PD trip, we (two of us) set out with a goal in mind- 1000 verified PD kills in two days.

Well, we failed. Only got 964. >

Man, we tried, all the way up to no light Sunday night.

Feeding isn't 100%, it needs some work. More like 70%. The Savage bolt face is a little large in diameter for the lower lip of the bolt to pick up the rim of the case all the time, if the mag rocks out of position slightly it won't pick up the next round. What I need to do is put a small pin on the bottom of the bolt face, and broach a channel for it in the receiver. There were several 20 shot strings that resulted in 15+ kills and no feed issues, there are one or two mags that work better than the others. Better get working on it, first trip this year is early March!