Wrong recoil spring.
Target 1911's for light loads have lighter recoil springs. Possibly, someone was shooting standard loads and installed a standard spring.
WARNING: just sticking in a lighter spring before making SURE the spring is the problem can cause battering and cracked frames.
Eliminate other problems first.
An extractor that's badly fouled, chipped, worn, or mis-adjusted can cause stove piping.
Disassemble the slide and remove the extractor. Clean it and it's tunnel in the slide thoroughly.
With the assembled slide off the gun and the extractor and firing pin etc. in place, slip a LOADED (Careful) round up under the extractor and turn the slide right side up. The loaded round should not slip out of the extractor. If it does, the extractor needs to be re-tensioned.
Without the proper amount of extractor tension, the fired case can slip out of the extractor and can stove pipe.
The ejector is seldom a problem, but check it for a worn, altered, or damaged face.
Check to insure it's firmly in place and one of the pins that fit into the frame hasn't broken off. This is tested by checking the ejector for looseness or if it can be turned on the frame.
Check the chamber for excessive fouling, pitting, rust, rings or bulges.
Use a bronze chamber cleaning brush from Brownell's to scrub the chamber.
Stick it into the chamber and twist a few times.
Inspect the cleaned chamber.
Try different ammo.
Some guns just don't "like" some ammo. Make sure the ammo is compatible with the recoil spring. Again, shooting standard load ammo in a gun with a lighter target recoil spring, can damage the gun, shooting light loads with a standard weight spring causes jams.
It's possible to cause stove pipes and other problesm if you "limp wrist" the gun. This means you're not holding the gun firmly enough and with a locked wrist.
There's really no good way to tell what you have in the gun since they all look pretty much alike.
The standard 1911 spring is a 16 pound.
The Gold Cup and most National Match guns use a 14 pound spring for use with light Mid-Range loads.
Recoil springs are available from 10 pounds to 24 pounds.
Best way to eliminate a spring problem is to decide what ammo you want to shoot then buy a new recoil spring for that load from Brownell's.
The other weight springs are to fine tune a gun for use with specific hand loaded ammo.
Thanks everybody. It just started doing this. I built the gun after I graduated from the Rock Island National Match Course many year ago and was working fine for a long time. It has been in my gun safe for about ten years before I started to shoot it again and it's been stove piping ever since.
Most of my ejection problems traced back to the extractor. EGW website has excellent info on extractor tuning. I was able to learn everything I needed to make my guns run 100% by using info on their website. Tension and radius of extractor are everything for reliable ejection. There is also info on shaping the ejector to get the cases to eject where you want them. If you carefully prep the extractor and ejector you can get all your brass to fall in a very consistent pile. I bought a weigand extractor tension gauge set which helps get proper tension easily for 9-38s-40-10 mm-45. Also fitting an oversize firing pin stop makes ejection very consistent. All the info on the EGW site enabled me to make my guns run like a pro.