SA 1911-A1 Firing Pin/Spring Question

I bought an older mid '90s (pre-ILS) SA 1911-A1 that was set-up as a wad gun (Clark rail, Red dot). I get light primer strikes with my hand loads. I fitted a new EGW firing pin stop (the existing one was really sloppy) which is about 0.006" thinner, and left the back corner at the stock 0.015" radius, figuring that all might help (which it did somewhat). The pin is within spec. for length (2.292") and protrudes about 0.032" behind the firing pin stop. The pistol came with a very light and shorter (1-5/8") firing pin spring. There is no apparent binding when I press the back of the (SS, 0.075" diameter) firing pin. I'm loading Starline once-fired brass (0.890" case length), and I ream out the primer pockets before reloading. WLP primers, seated below flush, so I don't believe primer movement is an issue. When the problem first occurred, I'd pull the round, and it appeared to be a decent primer dent (however, all are noticeably off-center). I'd re-chamber the round, and on the second strike every one of them fires. These same loaded rounds...never a problem with my Colt 1911. Try different primers? Modify it for the 0.090" firing pins? I don't mind spending some money...it printed some good groups in my Ransom rest.

Have you replaced the main spring? There is a firing pin spring and a main spring. You mention the firing pin spring, but the length you state sounds more like the main spring.

Try a new 19# main spring.

No...and I'm not sure what it came with. If I go with something heavier, I assume it could affect cycling?

Not very likely with a 19 lb mainspring, unless you switch to a stock 23 lb spring and you are using a .22 conversion kit. 

We're not talking about replacing the recoil spring here, which could have a considerable effect on cycling.

I am having same problem wit my RO I put after market EdBrown firing pin in and still have some problems with light strike, was looking at how things fit and I see that with slide off the hammer has a lot of play when you let it down I am thinking it might need a longer hammer strut, is there such a thing? have you tried longer strut ?

There are longer hammer struts out there. EGW for one.
Check to make sure you have enough overtravel on the trigger and your hammer half cock isn't hitting the sear. That will cause ignition problems.
Jon

With the off centered firing pin strikes.  Is it possible that the frame lugs were dressed up some, upper barrel lugs taken down to much and to correct this was linked higher?
If you look down the barrel of an empty gun does the firing pin look centered in the barrel?
I'm not a gunsmith but the off centered strikes would seem to indicate something more than just a firing pin or spring problem.

Virgil

Virgil I haven't seen a off center firing pin strike issue since the late 80's. Newer barrels typically do not present that problem anymore. The Bo-mar Accuracy Tuner, the Giles welded slide tabs, and barrel shimming were the fix of the day back then. Oh yeah the Clark offset firing pin bushing. In my experience you can really off set a firing pin strike and still get good ignition. It would have to be extreme in my opinion.
Jon

My wad gun occasionally has light strikes if I use CCI primers (1 out of every 100-200 shots or so). Runs flawlessly with Federal primers. Probably the easiest thing to try.

I believe I have the Ed Brown pin installed, based on the photos and the fact that it's strongly magnetic. I tried the EGW pin, but it's quite a bit shorter. Photo shows extreme examples of off-center hits. I looked down the barrel but my eyesight isn't good enough to see if the firing pin is off-center in the barrel (but it must be?). Overtravel seems adequate, and at the half-cock position I can't pull the trigger and drop the hammer (I assume that was what Jon was referring to). BTW it's a SA barrel. I could take a sharpie and mark a vertical line on the back of a primed case, then orient the line vertically when chambered. Fire the primer and see if the off-center hit is on the line and noticeably below center. That would indicate to me that perhaps the barrel is sitting high (vertically)?

Jon Eulette wrote:Virgil I haven't seen a off center firing pin strike issue since the late 80's. Newer barrels typically do not present that problem anymore. The Bo-mar Accuracy Tuner, the Giles welded slide tabs, and barrel shimming were the fix of the day back then. Oh yeah the Clark offset firing pin bushing. In my experience you can really off set a firing pin strike and still get good ignition. It would have to be extreme in my opinion.
Jon

Obviously you would know better than me and I trust your judgement and opinion.  I only asked because the OP said the gun was set up as a wad gun but we don't know who did the work.  If the person that set it up as a wad gun thought a new barrel was in order and it didn't get installed properly anything is possible.  I know myself, if I had a 1911 with the off center hits like the OP is showing I would start wondering why they were so off center and think that's the problem, but that's just me.
Again, I respect your opinion, not dissing you here.  Your work in the firearm industry speaks for itself.

Virgil

Pictures look acceptable to me based on 5 different 1911’s

Virgil,
On some slides the firing pin hole is centered before fitting the upper barrel lugs. I'll take properly fit lugs over centered strike any day. Yeah you could take it too far.
Jon

So go with a heavier mainspring (I'd have to figure out what I have now), and try Federal primers? For now I'd prefer not to re-barrel if I don't have to. Photo was my last group at 50 yards before I ran out of ammo, after realizing my Ransom grips were not tightened properly. WC mag inserted, first shot an intentional flyer, then six single-loaded. 185gr XTP, 4.0gr e3., 12.5# WC recoil spring.

Also, I know some of you do some Ransom testing. FYI a couple of the modifications I've made. One of my issues with it is the break-away friction torque due to the design and the annular friction material and pivot. The steel-on-steel pad contact (the height adjuster), IMHO, is very inconsistent when in the "reset" position (ready for the next shot). I feel that the upward force pushing on the pivoting system, therefore, is also inconsistent. For proper testing, however, this must be very consistent. So I installed a small neodymium super magnet as shown. Now when you re-set the unit, it is *noticeably* pulled down in it's resting place (even with a spherical pivot), but not with a sufficient force capable of preventing pivoting during recoil (I have not tested it yet with a .22 so that might change). I contend that this creates a more consistent force that the recoiling pistol must "break-away from" after firing. It should not matter if one day it's cool and humid, and another day perhaps hot and dry (this would affect break-away static friction torque). With the magnet, climate variations would only result in changes to the total angular displacement during recoil, but the breakaway force required does not change (or does, but very little). The second is installation of a cheap 1/4" bore ball bearing on the trigger bar, retained by two brass shaft clamps. The ball bearing is covered with a thin layer of electrical tape. My idea is that with this modification, since the outer race of the bearing is free to rotate, the force exerted by the trigger bar is always everywhere perpendicular to the surface of the trigger, regardless of trigger angle...never an upward or downward force component, which would act to lift or lower the pistol within the grip. It's noticeably better with longish roll triggers like my Sig P210A-9. Anyway...

tovaert wrote:So go with a heavier mainspring (I'd have to figure out what I have now), and try Federal primers?

Just go with a new spring for now. 

I suggested a 19#, as it should ignite any primers without issue. If it doesn't, that would indicate to me that something else must be going on to cause poor ignition. 

Also make sure that the rounds are seating fully in the chamber and that the primers are seated fully. The firing pin and channel should also be clean and dry. No oil or grease.

So I replaced the mainspring with a 19# spring, fitted a new firing pin stop (the one on the gun was really worn), scrubbed the firing pin channel, and loaded up a 30 rounds with Federal 150 primers. All good! Thanks for the suggestions.

Sir would you try a 100 Blue Box Federal Primers! I bet your issue will go away! Don’t change anything else! Just the primers

James Hensler wrote:Sir would you try a 100 Blue Box Federal Primers! I bet your issue will go away! Don’t change anything else! Just the primers

Lol I didn’t read your last post! I had a good feeling the Federal Primers would do the trick