70 series National Match

[1 LT MPC]

I want to convert my 70 series Colt to shoot 230 FMJ ball ammo. Anyone have suggestions? I assume I'll have to change some springs as the original ones seem to be on the light side.

 

[loose noose]

I've got a Colt Gold Cup 70 Series National Match, bought brand new in '72, I've shot just about every kind of loads thru it, including a bunch of hand loads, and have never changed the springs that came with it. It still shoots every kind of ammo imaginable. I've got buddies that also bought the gun and have changed springs, for exceptionally light loads, and the heavier loads. To be honest I've never been able to tell the difference, with the springs it came with. Note I carried that pistol as a law enforcement officer for 16+ years also.

 

[1 LT MPC]

45 colt

Thanks for the reply. I have shot 230 ball in my Colt as well, but there seems to be a lot of slide slam with these light springs. I think I switched the 16# slide spring to a 18# and it tamed it down some. I also changed the firing pin spring to a heavier one and that helped as well. I'm just wondering if that's all I need to do. I don't want to mess up this "classic" pistol. As I understand it, the National Match was designed to shoot 185 grain semi wads, but they don't feed well in my gun. I guess I'm trying to figure a safe way to shoot ball ammo without reloading, as I have no 45 dyes.

 

[Jim Watson]

A Series 70 Gold Cup is the same construction as a Gov't Model except for the adjustable sights and wide trigger. Many years ago Skeeter Skelton shot one 5000 rounds of hardball and it was more accurate when done than when he started.

It probably came with a recoil spring clipped to handle target loads, a standard recoil spring should be enough. If you are nervous about it, get a buffer and a small radius firing pin stop.

 

[loose noose]

If I remember right, I believe we went to the 185 grain hollow point by CCI Lawman back around '75 or 76. We used to shoot those once a year at qualification, and never had a jam etc., and we were issued new ammo at the end of qualification. You might try and see if you can get an original spring for the Gold Cup. I've shot a lot of 230 grain ammo thru mine and never had a problem. In fact we were issued 230 grain hard ball initially, and when we had a qualification we also shot 230 grain hard ball. I've got no idea how many pounds my recoil spring is.

 

[1 LT MPC]

I've got the original spring--it's the one that slams the slide. The old national matches had an 11# recoil spring but I think mine has a 16# as original.

 

[1 LT MPC]

Thanks Jim, but I believe the 70 series has an undercut slide that makes it lighter than a plain 1911 slide. Probably where my trouble originates.

 

[rcmodel]

In earlier years, the Gold Cup was tuned from the factory to shoot 185 grain mid-range match only.
It had a lightened slide, and a lighter recoil spring.

Hard ball would beat them loose in short order.


But by the time the Series 70 came along, it was a 230 grain hard-ball gun all the way.

You need a standard 16 pound recoil spring and a 23 pound mainspring to put it back to factory specs.

rc

 

[Jim Watson]

All I know is that neither of my S70 Gold Cups had "undercut slides".
That generally passed in 1970 although I have heard of some overlap.

There is no need for belief, look inside.

My normal ammo was intermediate between ball and midrange.

 

[HighExpert]

I think I would all a recoil buffer pad just to help the frame out.

 

[1 LT MPC]

I field stripped it and it does have the undercut slide. The serial number is 306xx so I assume it's an early one. My dad bought it about 1970. I also think I found out why it isn't feeding the 185 semi wads. I counted the loops in the slide spring and there were 32. The coils are also pretty thick. I think a 14 pound spring would let me shoot the low powered stuff. As long as I've got the heavier spring, I wont worry about damage.

Thanks for the help.

 

[BBBBill]

Pre 70 Gold Cups had weight relieved slides similar to some Commanders. The area behind the bushing and ahead of the locking lug recesses was bored out. Additional weight relief was done under the extractor, leaving it exposed through the bottom of the slide. Additionally, the bushing was cut to accept a special recoil spring plug with a beveled nose.

Beginning with the Series 70 Gold cups the guns were shipped with two recoil springs, one for light loads and one for hard ball (same as the regular Gov't Model). The collet bushing was introduced and the spring plug returned to standard configuration.

 

[Jim Watson]

Again, MY S70 GCs did not come with two springs, that was a later feature.

 

[loose noose]

Nor did mine come with two springs.

 

[BBBBill]

Can't tell you when Colt began shipping the GC with two springs. Mine did. Several of my friends' did also.

 

[Wireman]

I did not know about undercut lightened slides on Gold Cups. The OP observed that the recoil was noticeably greater with 230 grain ball. I would hope so. That's not a sign of trouble. What is incorrect is the idea that the gun will respond more politely with different weight springs. Recoil springs won't "tame" the recoil. They are there to chamber the next round. A stock 23 pound hammer spring, on the other hand WILL have the good effect of spreading out the recoil profile. If this GC seems snappier than a regular 1911, it is because it has less total mass, and not because the slide is moving faster.

WM

 

[1 LT MPC]

I think RC Model is correct. His post brought back a memory of my dad saying that this pistol was set up to fire 185 grain match ammo. I found one of the packages for the recoil spring and it is a 22# Wolff. I suspect that dad replaced the original spring with a heavier one at some point, and then reinstalled the original. My dad was a fan of the 230 FMJ. The notion that a light recoil spring will not slow slide speed depends on the mass going out of the barrel and the powder charge to propel it, in my opinion.

 

[Kp321]

My Series 70GC, bought in 1974 did not come with two springs and does have a lightened slide. Feels like a 10 or 11 # recoil spring and also a lighter mainspring, maybe 20# or less. I only shoot target loads in mine which it handles very well. If I did not have a hardball gun I would run a 23# mainspring and an 18# recoil spring in the GC. Be sure to replace the firing pin spring too, as already mentioned.

 

[Slamfire]

My Les Baer Wadcutter came from the factory with 13 pound progressive spring and they also told me, don't shoot anything heavier than 200 grains. My pistol has a Red Dot mount on the slide, and that extra weight will beat up the frame on recoil.

I have installed 22 lb Wolff progressives in my other M1911's and I had perfect function will full power ball ammunition. Go buy a 16 pound or 18 pound Wolff and go shoot ball ammunition. One should work fine, maybe both.

 

[bannockburn]

When I had my Series 70 Gold Cup I used a Detonics Competiton Recoil System in it. Worked perfectly whether I was shooting IMI Match 185 grain target ammo or 230 grain Ball ammo though it.

 

[larryh1108]

As has been mentioned. I'd replace the mainspring with the original factory spring for the standard 230gr ball ammo, 23# I believe. That will help more than a stiffer recoil spring but both, together, will be the answer.

 

[RecoilRob]

A small radius firing pin stop was mentioned by Jim Watson (post 4) earlier...and shouldn't be ignored as this is the key to delaying the slide movement and combined with a full power hammer spring should allow you to easily use hardball without resorting to heavy recoil springing.