I have a Kart Nm fitted on one my guns and shoot 3.8gr of Bullseye (200gr LSWC at 1.250 oal) with a standard 16# recoil spring. This load (which I produce with my inferior press) works in all my 1911's with a standard spring.

 

Thanks for that info, CT911.

Don

 

Can someone please give me approximate charge weights that are suitable for a particular weight recoil spring?

I don't have a Kart barrel, but have shot lots of rounds thru lots of gov models
(two of which are Gold Cups)

The lightest load to date is 185gr over 3.5gr Bullseye for a whopping 660fps
That runs fine with a 12# spring
Even runs in most gov models w/stock 16# spring.
Though spent brass barely dribbles out and last rnd slide lock isn't always a sure thing

I will be using a 200gr H&G 68 clone at an OAL of 1.250"

I've pretty well settled on 4.2gr Bullseye for such .
It's proven to be accurate and mild with enough guts to cycle all my stock sprung pistols

..L.T.A

 

The lightest load to date is 185gr over 3.5gr Bullseye for a whopping 660fps
That runs fine with a 12# spring
Even runs in most gov models w/stock 16# spring.
Though spent brass barely dribbles out and last rnd slide lock isn't always a sure thing

Thanks guys. Cappi, thanks for that load data for a 12# spring. I just picked up some WST, so the Bullseye will have some competition for loads. Got 8# for $125 - Feeling real good about that.

Don

 

When I started shooting 1911's back in the 60's I was into Bullseye competition and all of the ammo I shot was low-powered target loads. This was before the internet so we didn't have all this good info about tuning your recoil springs to your loads, so in my ignorance I just used the stock 16# spring. Worked fine.

Now that I've learned a little more, I have gone down to 14# (and even tried 14# variable) for my target loads. Couldn't really tell any difference in accuracy, function or perceived recoil with any of the springs.

 

Like the other guys said, with a #68 bullet 3.5 to 4.2 BE works good. Then change your spring to get reliable ejection. Most likely you'll end up with the 14 or 16 and call it a day.

Note that a match bbl, by nature, usually has a tighter chamber spec.
You might have to adjust your crimp die to get reliable chambering.
Especially if you have to go down to the lower wt springs and the gun is dirty.

As far as powder selection goes, BE is the old standard. I have used 700x with good results.
I've used a ton of ww231 but never went lower than 4.8.

 

Proper springs for a 1911 .45acp with light loads.....

There are a lot of variables that will affect / determine the proper weight of the recoil spring. For example: The weight of your hammer spring, the radius (or lack or) on your firing pin stop, etc.

Other factors also affect the springs chosen for a 1911......how tight the gun locks up and the amount of friction of the slide on the rails. However, as mentioned in the above quote the hammer spring weight (lbs.) has a great affect on the slide velocity for a given load. A standard .45acp uses a 23lb. hammer/main spring. When using light, mid-range loads, An 18-19# main spring might be appropriate for your gun, coupled with a 12-14# recoil spring.

I shoot light 9mm loads for IDPA. With my 5" STI Eagle with Kart barrel, and my reloads leave the muzzle at roughly 1030 fps with a 124 gr. JHP bullet. I use an 18# mainpspring with a 10# recoil spring. This allows my fired cases to eject about 3-4' away from the gun, and the gun is extremely reliable.

If you want to shoot fast and accurately with your 1911 .45, you may need to experiment to find the most accurate mid-range load of your choice with the proper balance of main spring and recoil spring. Proper sight tracking is needed to shoot fast, so you don't want a recoil spring that is too heavy, since it may cause the slide to slam shut (closes hard!) which may cause the muzzle to dip. Ideally, you want the sight to move straight up and settle back down to the original position when shooting fast controlled pairs. Since every gun is different, it is a trail and error process to find the ideal main spring and recoil spring combination for the load you most often use in your gun.....

 

An 18-19# main spring might be appropriate for your gun, coupled with a 12-14# recoil spring.

Thanks Rwehavinfunyet. Just ordered a 19# main spring and a 11# and 13# recoil spring. So now I will have 10#, 11#, 12#, 13#, and 14# springs. Question: gunsmith will be installing a EGW Oversize Firing Pin Stop - what will be the effect on my spring choice, and how much of a radius should I have him put on it? Thanks.

Don

 

What radius on a new firing pin stop.....?

Since you explained this would be used for a "wad" gun with lighter than standard .45acp loads, a standard radius on the bottom of the firing stop would be fine. A flat/square bottom firing pin stop helps with heavy recoiling loads, and will help to slow down the velocity of the slide when a round is fired.

If a gun is used for "hardball " matches, it may benefit from a flat bottom radius on the firing pin stop......

 

Since you explained this would be used for a "wad" gun with lighter than standard .45acp loads, a standard radius on the bottom of the firing stop would be fine. A flat/square bottom firing pin stop helps with heavy recoiling loads, and will help to slow down the velocity of the slide when a round is fired.

If a gun is used for "hardball " matches, it may benefit from a flat bottom radius on the firing pin stop......

My ball gun has a standard FPS. I've shot both, no noticeable effect with reduced (handloads), standard velocity (Federal GMM), and nearly+P velocity IMI TZZ Match to me.
I've not seen any recoil measurement/video that proves any benefit. What a flat/square FPS can do, is damage your hammer, if not properly radiused.

When I've asked Gunsmiths who support professional military service and Olympic Teams what they think, I get a range from doesn't matter to "maybe helps".
From the Bullseye/Guild Masters who are dedicated 1911 folks it is about an even split with bias toward being a mental benefit to the shooter.

The lack of consensus, to me, is an indication it doesn't matter.
But, put best by the AMU Gunsmith, if a Flat Bottom FPS makes you think you shoot better, why not.