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arkieron
March 5, 2012, 09:28 AM
I purchased a used loaded Springfield Target 9mm with what appears to be an STI Squared Match hammer. The ignition set was very polished and the trigger pull is a wonderful 2.75 to 3 lbs for USPSA competition. I tried a 17 lb mainspring with frequent light hits on CCI small pistol magnum primers (easier to get). I am now on a 19 lb spring which improved, but didn't cure, occasional light hits. I have a 20 lb. ordered, but wonder if I am overlooking part of the equation. I run a 19 lb in my Sig 1911 target that has a Wilson Combat hammer that never fails to ignite standard large pistol primers. Are the magnum primers that much harder or do I just need to keep increasing the mainspring weight until I get reliability? Both pistols have a Smith Alexander housing magwell and the strut is the same length as my Colt 9mm.

Unclenick
March 5, 2012, 09:49 AM
Some magnum primers are harder. Federal standard and match primers are easiest to ignite, IME, but I can't say I've compared their magnum primers to their standard primers for ease of ignition. You could probably call Federal or email them to ask.

With irregular ignition issues, I'd be double-checking firing pin protrusion. If your chamber is long and the rounds are headspacing on the extractor hook rather than the case mouth, an extractor with a slightly shorter breech-to-front-inside-claw depth could help, but be careful about feed reliability with that. It's not really how Browning intended things to work, even though it is very common that it does. If it still feeds reliably, headspacing on the bullet may cure the problem too (seating bullets only deeply enough that the head of a chambered round dropped into the barrel is flush with the back of the barrel extension (hood)). That keeps the head of the case back close to the breech face in the slide during ignition.

arkieron
March 5, 2012, 10:17 AM
Thanks unclenick. I just swapped the magwell (kimber) with my colt and noticed that I had some increase of load on the hammer with it down. The struts are very close to the same length. The Smith Alexander housing positions the mainspring cap .10 deeper than the Kimber which decreases the load to almost zero. Could I need a longer strut? I haven't compared with SA housing on my my Sig 1911, but that is next.

arkieron
March 5, 2012, 10:28 AM
One difference is the amount of cup in the mainspring cap. Looks like the one that was on this Springfield is unusually deep.

10-96
March 5, 2012, 11:18 AM
Yup, Springfield runs a different cup and strut I'm pretty sure it has to do with their infernal lock system. Just to keep things on an even keel, I ordered a strut, MSH, and a completed MSH pin/spring kit for the last Springfield I bought which the seller admitted to swapping parts on. He got frustrated, gave up, and simply put it up for sale.

arkieron
March 5, 2012, 12:05 PM
I am going to replace the cap and strut. thanks, Ron

Unclenick
March 5, 2012, 12:31 PM
Sounds like a plan.

I would still double-check the firing pin. Just push the firing pin in as far as it will go with a drift punch or small screwdriver or even just a toothpick. It should stick way out beyond the disconnector with the slide locked back in counter-battery. You just want to be sure it moves freely and that it's not dragging on the firing pin stop hole, nor is impeded by dirt or debris in the firing pin tunnel. You can also check that the shape of the pin nose is smooth and hemispherical and not chipped.

Springfield uses the same skinny pin for .45 and 9 mm and it seems to work OK on mine. You can also change out the firing pin return spring if you think you might have got one that's too heavy by mistake. Also, double-check that the original owner didn't find a titanium firing pin for it somewhere. Those low mass pins are famous for misfires. I took the one I had in my Goldcup out because of that issue. They may lower lock time but don't transfer inertia nearly as well as steel. Ditto for some of the skeletonized hammers.