How to get correct recoil spring weight for 1911

I am pretty new to the 1911, been shooting this SA RO for about a year. It still has (I think) the original (#16?) Recoil spring. I have found best accuracy with a Brazos 185 and 4.0 BE, but it won't lock the slide back, and occasionally fails to eject. I bumped up the load until it functioned well, but would like to drop back down for accuracy and recovery. I ordered the Wolff reduced power spring pack, but not sure how to know I have the 'right spring. I know to start high and work down until it functions, but is that it? Is there a way to easily tell if I get too low? I just don't want to start any unseen damage or unnecessary wear.

Patrick

I suppose a scientific approach could be calculated but for me I just let the brass tell me. I want the brass to make it to my net. Not fly over the top or dribble out under the pistol. If your brass is shooting across the range and smacking the shooter 3 lanes over then add spring. If the shells land about 2ft from where your standing (no net) then your just about perfect.

That's about where they land now with that load, so maybe the 15 will be the ticket. Sounds like I might be stressing about beating up the gun for not much reason.

Psween wrote:That's about where they land now with that load, so maybe the 15 will be the ticket. Sounds like I might be stressing about beating up the gun for not much reason.

Try shooting with two hands, with firm grip. If it locks back then, then you need to either grip it tighter when using one hand, reduce the recoil spring weight, or up the powder charge. Unless you are shooting hot loads, then a plus 1-2 tenths grain, may do the trick.

3.6 BE with 200 gr Brazos SWC functioned perfectly in my new RO. Interesting that yours is having an issue - not the same load but doesn’t sound that far off.

Maybe you have a tighter gun than mine?

Psween wrote:I am pretty new to the 1911, been shooting this SA RO for about a year. It still has (I think) the original (#16?) Recoil spring. I have found best accuracy with a Brazos 185 and 4.0 BE, but it won't lock the slide back, and occasionally fails to eject. I bumped up the load until it functioned well, but would like to drop back down for accuracy and recovery. I ordered the Wolff reduced power spring pack, but not sure how to know I have the 'right spring. I know to start high and work down until it functions, but is that it? Is there a way to easily tell if I get too low? I just don't want to start any unseen damage or unnecessary wear.

Patrick

i run my accurized range officer with 11 and 12 lbs recoil springs or try 12.5 https://shopwilsoncombat.com/Recoil-Spring-5-Full-Size-Chrome-Silicon-125-Lb/productinfo/703G-12.5/

I was taught by several gunsmiths that there's no exact math when it comes to selecting the correct spring tension. You should either start with the lightest spring and work your way up until the gun stops cycling reliably and has multiple FTEs and FTFs, then back up one. Or start with the heaviest weight and work your way down until the gun starts cycling reliably. And by reliably I mean I can go through TF and RF portion of the 900 match without any alibis. That is, if the ammo is right. 
My standard load is 200gr LSWC over 3.7gr BE, and one of my guns works perfectly using a stock 16 lbs spring, but one other gun only works when I put 12 lbs spring in it. And another one (with slide mounted Ultradot) needs a 10 lbs spring.
I think it's better to develop an accurate load and then tune your gun to it, not the other way around.

I have an accurized RO.  I'm running the 180gr Brazos coated with 4.2gr Bulleye and Wolff 10# spring.  I'm using a 30mm Matchdot II with a pair of heavier than usual (3 screws wide) rings and a full length pic rail.  I've also run 185 gr swaged lead over the same powder charge.  I may migrate to Zero 185 gr JHP, and I have plans to work on my loads and see if, or to what extent, I can reduce them.

The old favorite is a 10 lb spring. You can use anything from 10 to 12 lbs but use a buffer on the rod to keep the slide from battering the frame. My loads will cycle my ball gun pretty well. 3.8 grains bullseye or clays behind 200 grain swc.

RodJ wrote:3.6 BE with 200 gr Brazos SWC functioned perfectly in my new RO. Interesting that yours is having an issue - not the same load but doesn’t sound that far off.

Maybe you have a tighter gun than mine?  

I just got back testing Brazos bullets 185 gr SWC over 4.0 grains bullseye, old Remington no 2 1/2 primers, new Starline brass. .030 shoulder. Only 25 rounds in 5 round strings, but not a single hiccup.  Fired, ejected, locked back perfectly. Bone stock everything except old style pachmayr grips.

I must be missing something, but I cannot find 185 SWC bullets on the Brazos website.  I find 180s, which is what I've been using.  Do you have to call Brazos to get 185s?

AFAIK, those are the same bullet....they weigh out around 182-183 grains typically.

GME wrote:I must be missing something, but I cannot find 185 SWC bullets on the Brazos website.  I find 180s, which is what I've been using.  Do you have to call Brazos to get 185s?

I’m dylsexic… “45” and “180” equals 185.  Tony is correct that they are 180 gr.

    Sorry about that.

My oops in the original post, I'm shooting the powder coated Brazos 180 SWC, bevel base. I've also been experimenting with the Zero swaged 185 and got the numbers backward. In any case, they shoot well, as long as I can get the gun to function with them. I think I should be able to get there, the spring kit has 11#-15# springs in 1# increments , so one should work.

One benefit from the light loads/reduced spring set up is the GI grip safety tang no longer tries to burrow into the web of my hand.

There are there variables in 1911 slide dynamics; recoil spring weight, mainspring weight, and firing pin stop shape. Reducing mainspring weight will let the pistol function with a heavier recoil spring, needed if the barrel has a tight lockup. A square bottom firing pin stop will also reduce slide velocity. Experienced pistol smiths will juggle all three of the variables for proper operation and feel.

I'm also not using a dot, so I don't have that weight to deal with right now. I may put a reflex dot on at some point, so probably have to change springs again. Thanks for the help, I should get the springs today and will start testing.

Psween wrote:I'm also not using a dot, so I don't have that weight to deal with right now. I may put a reflex dot on at some point, so probably have to change springs again. Thanks for the help, I should get the springs today and will start testing.

Don’t sweat over the extra weight of a red dot sight. Unless you are on the ragged edge of function, the sight weight won’t make much difference. I run reflex sights rather than tubes but have not seen any difference in function after installation.

I swapped in the 15# spring with no other changes an fired 5 trouble free magazines. No FTE, slide locked back every mag. If it proves out over the next few hundred rounds that me be the easiest fix ever. Thanks for the tips and info.

Patrick

What is the common recoil spring for 1911 in 9mm when shooting 115gr?

I'm not seeing a response from our list gunsmiths but the other springs matter and have interplay; particularly the main or hammer spring. 

If you switch down to a softer alloy, all other things same, you may find it malfunctions. Same deal going up from standard cast to powder coated, those suckers are more slippery. That said, l think most common target loads are running 13 or less

Wolff spring shows these spring rates for the Colt 1911
[url=https://www.gunsprings.com/COLT/1911 GOV'T PISTOL/cID1/mID1/dID1]Springs for 1911 GOV'T PISTOL Semi-Auto Pistols (gunsprings.com)[/url]

COLT 1911 FACTORY RECOIL SPRING NOTES 
   1. Factory rating for super .38 & 9mm is 14 Lbs.
   2. Factory rating in .40 S&W is 19 Lbs.
   3. Factory rating for the Colt .38 Spl. Midrange is 14 Lbs. 
   4. Factory rating for the Colt Ace .22 conversion is 14 Lbs.
CONVENTIONAL RECOIL SPRINGS - .45 ACP Factory Standard.: 16 Lb.
Hammer Spring

• Factory Standard : 23 Lb.
  
  

Springfield uses an ILS (Integral Locking System) different type 30 lb hammer/mainspring since 2001.
[url=https://www.gunsprings.com/SPRINGFIELD/1911A1 SERIES/cID1/mID60/dID267#856]Springs for 1911A1 SERIES Semi-Auto Pistols (gunsprings.com)[/url]