Marvel Unit 1 vs. Unit 2 conversions


February 22, 2011, 05:35 PM
Was considering getting a Marvel conversion kit for my Springfield GI.45 Champion. It has a ramped barrel, but in correspondence I've had with Marvel the conversion kit should work.

I was comparing Unit 1 to Unit 2 and the accuracy of the Unit 1 conversions is impressive. The cost difference is approximately $100. Is it worth shelling out the extra money to get a super accurate conversion or should I just stick with the Unit 2?

I guess since I'm basically planning on using it as a plinker and a training gun I don't need that extra accuracy. Anyone else's thoughts?

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February 22, 2011, 05:37 PM
Personally I'd always take the most accurate available at a price I could manage. That way it's easier to correctly atttribute the misses ...

February 22, 2011, 05:47 PM
I shot my Marvel unit 1 today and i'm always happy with it.
I'm not sure if the unit 2 has the flexibilty to change sight ribs from irons to a scope. I enjoy this aspect.
Their customer service is top notch.
Spend the $, its less then two tanks of gas.

February 23, 2011, 10:43 AM
+1 on the Unit 1.
My only complaint would be the lack of the slide locking back after the magazine is empty. I always put a orange dummy as the bottom round in case I lose count.


February 23, 2011, 11:40 AM
Thanks for all the info folks! Putting into the "tanks of gas" put it into perspective.

For follow-up can anyone confirm that the Marvel units are compatible with a frame that is cut for use of a ramped barrel?

February 23, 2011, 01:19 PM
Yes, the Marvel will work on frames cut for a ramped barrel.
if you want a .22 conversion that locks the slide back on empty, get the AA conversion. It was designed by Bob Marvel and is an update to his original design's that Marvel Precision sells.

the Unit 1 will work with standard velocity ammo, while the Unit 2 calls for Hi-Velocity ammo, though i've read that swapping the recoil spring allows the use of std. velocity ammo.

The Unit 2 is still very accurate, and if you use it as a training simulator, the slide will function like your normal slide, where as the Unit 1 functions similar to a S&W Model 41

February 23, 2011, 01:43 PM
Ad Arms designed their conversion with the late Bob Brown as a consultant. Bob Marvel sells a "tuned" version of the AA Target model and used to supply them to STI, who I believe has now discontinued selling them. There's a substantial waiting period for AA 1911 conversions because they're going full-bore with Glock units. I think the website indicates around 3+ months.

I got the AA Target, with the optional lighter spring than ships standard, it works perfectly with SV rated 22 (CCI, Aguila, Federal) and with the std heavier spring, you can shoot the HV stuff. It does lock back on empty and, as was noted, has a fixed barrel with only the rear of the top end moving to eject/chamber rounds, a la the S&W 41.

February 23, 2011, 01:47 PM
If you want more details on the Advantage Arms conversions, I posted a review and photos of mine on here yesterday.

February 24, 2011, 02:48 PM
I really would like to get the AA conversion since the slide locks back, but a 13-14 week turnaround time is going to drive me crazy. I asked Marvel what their turnaround was and the quoted approximately one week. So I can shoot NOW without something that locks back or I can wait...and wait...and wait.

Does anyone know how the accuracy of an Advantage Arms conversion compares to that of a Marvel Unit 2 conversion?

February 24, 2011, 05:14 PM
I have never had any problems with the Marvel Unit#1. Never had the neesd for theslide to lock back after the last round. As an old bullseye pitol shooter I automatically count each time I fire.

ETCss Phil McCrackin
February 24, 2011, 05:47 PM
I have the Unit 2 Gov round top, and am running it on top of my Springfield Loaded carry gun. A couple of tidbits:

1. I found out the hard way that Springfield puts a 23lb mainspring in with their ILS as standard while Marvel uses a 17lb regular mainspring in their base frame for testing. My Unit 2 would not run for crap until I swapped my stock spring for a 19lb regular spring, thereby eliminating the ILS to boot.

2. The polymer mag sucked, I recommend dropping a little extra for the metal one.

3. The unit runs perfectly with high velocity ammo in the 1230 fps range, and CCI mini mag is the company's recommended diet.

4. With the lighter recoil springs (available from Marvel) the unit can be used with SV ammo.

In short though, I love it and find it perfect for cheaply practicing with my CCW piece.

February 25, 2011, 11:29 AM
Springfield's MS that is used with the ILS is 28# and not 23#.

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