40 to10 MM mod

[hogslayer]

Well I get my 10 MM barrel and springs tomorrow for my conversion of my springfield full size.  The gunsmith at Nowlin Arms recommends a 16.5 lb spring...... I am thinking that may be a little bit on the light side.  i also ordered an 18 lb spring.  am thinking it might even take a 20 lb spring for the heaver loads (my nowlin barrel is ramped and fully supported.)  Will post picts and a report after I see how it works.  Wish me luck,
Hogslayer

[The_Shadow]

Sounds like a nice project...assuming this is a 1911 build using the Nowlin bbl.  You didn't mention what make or model you were working with.  Be sure to post pictures and range reports on the experience both good and/or bad if issues occur.  Its all about learning from experiences as you work with any project.  Best of luck! 

[cmemiss]

Lots of folks going to 10 mm in a 1911 are using 22-23 lb. recoil springs along with Flat bottom firing pin stops and 23+ lb. mainsprings.  This is mostly an attempt to keep the ejected brass in the same county with full power loads. 

[harleyhopper]

Try the 20# recoil and a 22# main. My RI 10 does very well and the brass is 10-15 ft. I do have a flat bottom firing pin stop. I mean flat. Just kissed the back edge with a file to take the sharp edge off.

[hogslayer]

Yes it is a 1911 build.  Forgot to put that in the original post.  They are including a 16.5 and a 18 lb recoil springs.  Will start with them and see how she shoots.(and report on results of course)
Should come in the mail within the next hour and a half.  Patience?  don't have no stinkin patience.....   

[Yondering]

Use a heavy mainspring to delay unlocking in a 1911. Don't go any heavier on the recoil spring than you have to. The gunsmith you talked to was probably thinking the same thing.

16.5-18 lb recoil spring should be fine with the correct main spring, and will be less prone to battering the barrel bottom lugs.

[rainsdrops]

I converted a para p16-40 to 10mm
Hand reamed the barrel, and installed an 18lbs spring.  Not an issue.
No signs of slide battering or barrel lug wear.  I only use a heavier spring if I'm shooting mag after mag of heavy / hotter loads

[hogslayer]

I ordered an 18.5, 20,22, and 24 lb spring from wolf.  The barrel was suppose to be a drop in, of course mine was one of the 5 or 10 % that needs some fitting.  Will be next week before my smith can do it.  Springs should be in by then.  We will seeeeeeeee.

[denclaste]

I'm running 18.5# recoil, 24# mainspring, and Wilson FPS. All is well. Ejection still low earth orbit. RIA says theirs are shipping with 20# recoil and 22# main. If you plan on a steady diet of medium hot to hot hot you may want to consider my type of set up to save on wear and tear on your springer. 1911's in 10mm are great fun.

[Yondering]

Yes, good point, a flat bottom firing pin stop should be a requirement in any 10mm 1911.

[hogslayer]

Does any one have a pictures of there "flat bottom firing pin stop?
Thanks