[fatford]

what weight recoil spring would you use in a 9mm major open gun with 5" barr. and egw 8 port comp.? the slide has been flattoped and the rear site area has been removed. i know that type of load will play some factor in it . i`m just looking for a safe starting point. working toward a 170pf. thanks

[shooterbenedetto]

fatford, on May 9 2009, 12:49 PM, said:

what weight recoil spring would you use in a 9mm major open gun with 5" barr. and egw 8 port comp.? the slide has been flattoped and the rear site area has been removed. i know that type of load will play some factor in it . i`m just looking for a safe starting point. working toward a 170pf. thanks

assuming that you have a tuned magazine, tuned ejector, extractor, and good brass,
I would start at 8lbs then work it up to 10lbs. 8lbs is usually the magic recoil spring.

This post has been edited by shooterbenedetto: 09 May 2009 - 07:33 PM

[fatford]

thanks for your reply. i was thinking that 8# would be a good place to start.

[G-ManBart]

From what I've seen I think more folks are running 9lbs than 8lbs, but either is a good starting point.

[eric nielsen]

My slide & barrel/comp are almost the same as yours - slide weighs 10.5 oz.

9 lbs works really well at 171 power factor, hammer spring is 18lbs [I think].

This post has been edited by eric nielsen: 12 June 2009 - 05:45 PM

[dbltapipsc]

+1 on trying both. If you run hammers on a target and second shot is high, I would think your under sprung. Second shot low, over sprung. Also when the 8# sets, it will be less than an 8 by a bit. Just my .02 worth.

[Josh Biondi]

I think that 8 lbs is a good start point....

[luckylager]

What about on a shorty? Same difference?

[whatmeworry]

luckylager, on Jul 17 2009, 10:04 PM, said:

What about on a shorty? Same difference?

8# recoil spring will still be a good starting point. Figure a shorty has a slide and barrel which are going to be lighter than those on a 5" gun. No magic numbers regarding spring weight. Start with an 8# and see how it acts. Try 9# and 10# also.
Cya,
Pat

[HSMITH]

You open a package that says 8#, it might be 8, it might be 6, it might be 10. You shoot it a couple hundred rounds and it will be different again. Buy two of each and try them all, if it were me I'd buy a pair of 8's, 10's and 12's. Six springs won't break the bank and they should be enough different to get an idea of what is going to work for you. Buy or make a spring tester to find out what the actual weight of the spring that works for you is, and buy more. This brings to mind that Dave Re, or at least I think it was him, said that springs from Sprinco are actually tested and correctly packaged for sale. If you bought them you should be assured that at least the first couple hundred rounds are at the advertised weight and that subsequent purchases would be very close.

[luckylager]

My issue is spring binding. I'm running an MC 38 Super, and the only spring I can get in there without binding it a Wolf 8# Variable spring. Any ISMI binds up at slide lock, as does a Wolf 9 or 10#. I'd like to bump up to a 9 lb or even a 10, but hate the idea of clipping coils....

[HSMITH]

Clipping coils does not change the rate of the spring at all, it only changes the overall length of the spring at full compression. Clip away and be happy, also be glad that you can get a spring long enough to get the rate you want that you can fit to your application. Having a spring that needs a coil or two clipped isn't a bad thing. I like to see a full coil short of coil bind after clipping, springs that don't go solid by a full coil last a world longer than springs that almost go solid.

[luckylager]

Agreed. So what's the proper method to fit a spring to the gun?... Pull off the top end and go by trial and error? I'm very interested in the matter, as this has been a sore subject for a while...

[HSMITH]

Take the spring out of the gun, reassemble with all parts but the spring, retract the slide fully and mark the slide and frame. Assemble with new spring, clip one full turn until the marks line up, then one more full turn. If it is a reverse plug set up you can also take the guide rod out and clip until the reverse plug touches the guide rod head and then one more full turn. Be careful though, a reverse plug hurts if you slip LOL.

[luckylager]

I'll tinker this morning and let you know how it goes... Thanks HSmith.

[luckylager]

OK, got it fitted, but it cost me 6.5 coils off of an ISMI 9 lb spring. Sound excessive? The gun is one of Derek's shortys.

[ogiebb]

luckylager, on Jul 18 2009, 07:46 AM, said:

OK, got it fitted, but it cost me 6.5 coils off of an ISMI 9 lb spring. Sound excessive? The gun is one of Derek's shortys.

dude you cut half the spring????

[luckylager]

ogiebb, on Jul 20 2009, 05:54 PM, said:

luckylager, on Jul 18 2009, 07:46 AM, said:

OK, got it fitted, but it cost me 6.5 coils off of an ISMI 9 lb spring. Sound excessive? The gun is one of Derek's shortys.

dude you cut half the spring????

I'll just have to have you fix me up when I come see you in November. No signs of battering, but I'm on the fence about how I feel the gun tracks.

[matt2ace]

eric nielsen, on Jun 12 2009, 08:44 PM, said:

My slide & barrel/comp are almost the same as yours - slide weighs 10.5 oz.

9 lbs works really well at 171 power factor, hammer spring is 18lbs [I think].

+1..........Started with an 8# when the gun was new and moved to a 9# after about 2500 rounds with same essential setup as you have.

My gunsmith recommended 9-10# as a final weight once the gun is broken in.

[XRe]

HSMITH, on Jul 17 2009, 11:28 PM, said:

This brings to mind that Dave Re, or at least I think it was him, said that springs from Sprinco are actually tested and correctly packaged for sale. If you bought them you should be assured that at least the first couple hundred rounds are at the advertised weight and that subsequent purchases would be very close.

Yeah, that was me Based on conversation w/ the owner of the company, and being shown his spring weight test jig in person In my old gun, I put 15K rounds on a Sprinco 10# spring, and then measured the spring - it was still 10#. These springs just flat out rock.

[Dave Gundry]

HSMITH, on Jul 17 2009, 11:48 PM, said:

Clipping coils does not change the rate of the spring at all, it only changes the overall length of the spring at full compression. Clip away and be happy, also be glad that you can get a spring long enough to get the rate you want that you can fit to your application. Having a spring that needs a coil or two clipped isn't a bad thing. I like to see a full coil short of coil bind after clipping, springs that don't go solid by a full coil last a world longer than springs that almost go solid.

Be aware though, that by clipping coils off a spring, you change the amount of force needed to fully compress the spring. For some reason, gun spring manufacturers measure or rate springs by the full compression force (lbs) rather than spring rate (lbs/in or force per unit length). To really understand what works (and why) in your gun, follow Howard's method, then measure them on a spring tester (easy to build). Once you know what numbers you need to run properly, you can buy and verify new springs by weight and compressed length.

[luckylager]

Dave Gundry, on Aug 1 2009, 11:15 PM, said:

Be aware though, that by clipping coils off a spring, you change the amount of force needed to fully compress the spring. For some reason, gun spring manufacturers measure or rate springs by the full compression force (lbs) rather than spring rate (lbs/in or force per unit length). To really understand what works (and why) in your gun, follow Howard's method, then measure them on a spring tester (easy to build). Once you know what numbers you need to run properly, you can buy and verify new springs by weight and compressed length.

I did end up building a spring tester, and found that the cut springs measured out very close to their specified weight just as they approached coil bind. At the slide-back mark on my tester, it was usually within 1/2 a pound off of the uncut weight, and about a pound difference at the slide forward mark. You guys weren't kidding about how the springs may not be their marked rate, half of them were off by 2.5- 3 lbs.

[blkbrd]

sounds like you have a Commander slide.

[luckylager]

I don't have the actual dimension, but I believe it is a Gov. model slight slightly cut down, and slightly longer than a commander slide. Makes finding a recoil spring a challenge.