40 S&W to 10mm conversion

elmo123 · February 08 2015 06:14:24 AM MST

Hello, I recently purchased a RIA 1911a1 Tact 2 pistol in 40 S&W and have purchased most of the parts to fit a 10mm barrel to this pistol. What pound recoil spring should I use ?

Thanks, Mike

10mmfan · February 08 2015 10:05:30 AM MST

Mine runs best with a 18 1/2 lb spring, any higher I get feeding issues.

sqlbullet · February 08 2015 02:32:53 PM MST

I run an 18.5 too. I also run a flat bottom fps with a 25 lb mainspring.

elmo123 · February 08 2015 05:19:27 PM MST

Thanks for the responses I have ordered an 18.5, 20 and 24 lbs springs from Wolff but I still need a barrel link and pin. I have been shooting a 40 since they came out but I have never worked with the 10mm yet and I am looking forward to it.

sqlbullet · February 08 2015 09:36:30 PM MST

When you order your barrel link and pin, add a EGW oversize firing pin stop. It will require minimal fitting. For the edge that rides against the hammer...Just barely break that edge with a fine file. nothing more. It will do a ton for slowing down that slide.

elmo123 · February 13 2015 04:37:27 AM MST

The barrel from RIA arrived yesterday and it was the same dimension as the 40 barrel so this installation was simply a drop in. I did have to trim the ejector back a few thousands to get a loaded 10mm round to eject. Does anyone know what pound recoil spring is used in the 40 S&W?

sstewart · February 13 2015 06:47:45 AM MST

You might want to try posting in the 1911 forum in RIA section. I would be surprised if Mity doesn't know this.

kilibreaux · March 25 2015 05:02:00 AM MDT

Always start with the heaviest spring you have....22# is good and work down from there.
It also depends on what type of 10mm you are shooting....the world has FULL HOUSE 10mm which needs maximal spring rates, and mid-range which can live okay with middle-weight spring rates. If you are shooting any of the "generic" OTC 10mm ammo you can get by with 18# but if you are planning to shoot real performance 10mm such as Underwood you should go with a 22# to start.