SVI INFINITY Problem.

[rr4406pak]

I have an SVI INFINITY 5" Limited .40 S&W long dust cover gun.

I'm getting light primer hits.

I would have only one light primer hit at a match and now I'm getting multiple light primer hits. It is getting worse.

I did the "pencil test" where you put the pencil down the barrel of the gun and fire the gun pointed at the ceiling and see how far the pencil jumps. The pencil only pops out about 10 inches. Sometimes barely making it out of the barrel! My stock Colt .45 1911 can hit the ceiling everytime!

The firing pin channel is clean and clear. Firing pin moves freely with no visible damage.

When you look at the firing pin hits on the spent brass you can see everyone is different. Some have good hits some have bad hits. (It is not the ammo)

Any ideas how I can fix this serious problem?

Anyone ever have this problem in their SVI?

Thanks.

Edited April 1, 2008 by rr4406pak

[grandbagger]

im using extra long firing pin from limcat, never had any light primer hit.

[BOGA]

On my svi, the bolt that holds the interchangeable breech face restricts the firing pin spring compression and limiting the forward reach of Fp. guys on my club suggested to change the FP to limcat extra long and it solved the problem

[titandriver]

rr (Road Runner?) --- don't forget to cut the firing pin spring. Because of the ICBF the spring needs to be about 75% of the length of a standard spring, at least that's the way it is in all my ICBF SV's.

[Skywalker]

I have a similar SVI (i.e. .40" cal., 5", long dustcover, ICBF) but never experienced such a problem.

Maybe it could be useful if you can list the main spring rating: I have been able to reliably go as low as 15# main spring coupled with an 11# recoil spring.

I have always used CCI small primers.

Which primers are you using? Perhaps hard, magnum or rifle ones?

Could you post pictures of primers from spent brass where the round went bang, and where it didn't?

Having said this, I'd advice to check the thightness of the ICBF hollow screw: if it backed out, it's possible that it's limiting the firing pin travel, resulting in light hits.

On a side note, I never, ever, had to cut the firing pin spring, even though my gun has the ICBF: I've always used untouched factory springs.

Edited April 1, 2008 by Skywalker

[DonT]

Was having the same problem on new SVI open gun while trying to work up a major load. Primer flow and light strikes. Installed Mclearn? extended firing pin and it helped with primer flow but could tell it wasn't going it's full travel and was still getting some light strikes. Installed an SVI extended FP and it helped some more and it was going it's full travel but still some light strikes. Switched to federal primers, no more light strikes.

[ahtsay]

Maybe your primers are not seated deep enough. If the primers are even a little "high", it will cause light strikes. As the firing pin hits the primer it tends to push it down instead of igniting it. Try to put your ammo on a flat surface. Then gently push at it. If the ammo rocks back and forth, then your primers are too high. Hope this helps.

[Religious Shooter]

If the breechface is loose... there's your problem.

[shooterbenedetto]

sounds like problem are breach face, change to extra long firing pin and change your main spring lbs up!!

[Jasonub]

things to check:

1 check if the breechface is loose- if so remove, clean properly degrease add locktite 262 or 272 generously and tighten wait 24 hours before putting back your slide back together

2. check length of firing pin spring, cut the spring till its about as high as the firing pin end.

3. get a limcat xl firing pin

4. i use a 15 pound ms ismi and never had problems with the original sv firing pin. i just replaced it with a limcat since its longer

[bulm540]

ANd it could be a case of high primers. Check your reloaded rounds.

[rr4406pak]

It is 100% not high primers. Does the same thing with factory ammo. That was my first check.

This gun just does not hit the primer with authority or consistency.

Upon inspection of the slide it looks as if the breechface is tight. I see and feel no gaps.

How can I tighten the breechface anyway to make sure?

I do not see anywhere to tighten it...

Thanks.

[L9X25]

R440,

How about some background on this gun ... is this a NEW SVI gun, or one that you purchased from an individual?

If it is new, we will know that everything in the gun is a factory SV part and it should work. If it is a used gun, several parts, including the firing pin, FP spring, and mainspring may have been changed by the previous owner.

I can tell you from experience that the SV guns usually do not have ignition problems as shipped from the factory and the most common aftermarket cause is using an uncut extra power firing pin return spring. From that point, I would look at trash in the FP tunnel and expand my search from there. If you are finding trash in the tunnel, harder primers and longer FP might resolve your problem completely.

The breechface is tightened through the firing pin hole, but it is a hollow bolt and you should NOT ovetighten it for fear of shearing the bolt. Unless it is noticeably loose, leave it alone.

Let us know what you find.

Leo

Edited April 1, 2008 by L9X25

[Mick]

It is 100% not high primers. Does the same thing with factory ammo. That was my first check.

This gun just does not hit the primer with authority or consistency.

Upon inspection of the slide it looks as if the breechface is tight. I see and feel no gaps.

How can I tighten the breechface anyway to make sure?

I do not see anywhere to tighten it...

Thanks.

Take the firing pin out. It (the FP) goes through the nut that holds the breachface.

A 1/8th" allen wrench is needed to check it. If it is loose it is a problem. Use blue locktite but if it continues to loosen use a SMALL amount of red. If the threads are bad get a new face and/or nut and they will need to know the marking on the front ie..."40K" or whatever it says.

Also try a longer firing pin with that adjustment. SV should have some as does Limcat.

Edited April 1, 2008 by Mick

[moverfive]

you have already answered your question - if the pencil is barely making it out of the barrel, then odds are that your main spring (hammer springs) needs to be replaced. The pencil should clear the barrel and then some in order to pass that test. Anything less is asking for light strikes and thus the occassion non-fire.

......and have you recently had someone do a "trigger job" for you? This is usually the culprit, the poor man's trigger job, where the main spring will be cut too much in order to simulate a light break.

[rr4406pak]

Breechface seems tight.

I received this response DIRECTLY from SVI:

Keith,

I would suggest looking at replacing the mainspring to a new 17lbs spring and then going to an extended firing pin. The mainsprings and recoil spring will get weaker over time and it is important to keep them changed for best results. We have these products in stock for immediate shipment. You can order by phone or email.

Regards,

Brandon

From that, and all the responses, I figured I would try this first.

So I ordered a DP Hyper Drive Extended Firing pin and 17lb mainspring from Shooter's Connection.

I could not find the Limcat XL FP anywhere. No one has them.

Are there any tricks to changing the main spring? You just remove the mainspring housing from the gun and then push out the pin on the main spring housing correct?

Again, thanks to all for the responses!

And to titandriver , Yep! Sig means Roadrunner 440 six pack (and yes I have an all orig 1970 Lemon Twist Super Track Pak RR) .

To Skywalker: I bought the SVI used so I do not know what the current weight of the main spring is.

I am using Magtech small pistol primers. I will try and post pictures of the light primer hits so you can see the inconsistent levels of primer strikes from shooting a single stage. Yes I picked up all the brass and kept them separate.

To L9X25: As for background on the gun... I bought it used from a member of these forums in excellent condition.

To moverfive: I have not had a trigger job done since I have had the gun. I would have to contact the previous owner of the gun to find out if he had any work done on it.

[titandriver]

Sure wish I had my '70 Challenger T/A back! That and a '67 Corvette fastback coupe. Totally trashed both of 'em to make 'em drag cars --- gotta say it was fun though!

[jam-man]

Is it possible the gun is firing out of battery and that is why you are getting different primer strikes on brass? Is the strikes not centered? High low etc.

[Mick]

If what Brandon said isn't quite enough try a 19# mainspring.

I use 17# allot but quite a few folks use rifle primers and the heavier spring helps.

[Don_B]

One other thing that is often overlooked is the overtravel screw on the trigger. If it has moved in and shortened the overtravel excessively that will cause the sear to hit the halfcock notch on the hammer and slow the hammer down. I have seen this happen many times and it is often overlooked.

You need to have approximately 1/8 inch of overtravel on the trigger.

If this is happening you can see the marks on the hammer and sear.

[Jasonub]

speedshooter.com has the limcat firing pin.

hope the dawson drops in. the m2i doesnt drop in and the egw also does not drop in.

I had to remove some material with my limcat ext firing pin but not much for it not to bind

magtec is known to be hard though i never had probelems when i tried it in my sv.

[sinnsyk]

Don

Couldn't agree more.

Should be thoroughly checked by holding the trigger all the way in while pulling the hammer back/forth. No snag and play between hammer/sear should be present. What may happen too, is if in the heat of fire, if you don't pull the trigger all the way back if you're doing a lazy trigger slap it could be a problem related to inconsistent trigger travel on the shooter's part. Only a problem when you have a real light trigger and you're extremely sensitive to riding the trigger to a fine edge. For DA guns it can be more prominent.

[rr4406pak]

Jasonub,

I just looked at speedshooter.com and their website shows:

LM2 Limcat Firing Pin XL Out of Stock

Is there something you know that we don't?

Also, where on the firing pin did you have to remove material and what did you use to remove it with?

DonB,

The overtravel adjustment was actually the first thing I tried.

I tried screwing it in and it locked up the trigger.

I moved it way back and I could fire the trigger again but I still had poor firing pin hits (as evidenced by the pencil test).

Where should I set my overtravel at anyway.

At first I thought that the screw in the middle of the trigger was there just to let you change out the interchangeable triggers...

[L9X25]

R440,

In response to folks that purchased aftermarket XL firing pins, and had to modify them to work properly, SV now manufactures one of their own. Theirs is designed to drop into their IBF guns without modification. Other manufacturers may have to be modified to work with the slightly different dimensions in the tunnel due to the IBF. I would stick with SV's and they will cover you if you should experience any difficulty. Other folks are usually not too happy to hear that you modified their product.

YMMV

Leo

Edited April 2, 2008 by L9X25

[Don_B]

Jasonub,

I just looked at speedshooter.com and their website shows:

LM2 Limcat Firing Pin XL Out of Stock

Is there something you know that we don't?

Also, where on the firing pin did you have to remove material and what did you use to remove it with?

DonB,

The overtravel adjustment was actually the first thing I tried.

I tried screwing it in and it locked up the trigger.

I moved it way back and I could fire the trigger again but I still had poor firing pin hits (as evidenced by the pencil test).

Where should I set my overtravel at anyway.

At first I thought that the screw in the middle of the trigger was there just to let you change out the interchangeable triggers...

OK, a couple things, first, the screw in the middle of the trigger actually does 2 things. It's main purpose is to set the overtravel but with the SV trigger it is also used to secure the interchangable trigger shoe.

Next you need to adjust the overtravel. When you start turning this screw in you must be aware that too much force will actually push the entire trigger shoe off of the trigger bow. This may be what has already happened and could be the source of your trouble. Also be aware that either not enough or too much overtravel can both cause problems.

Anyway, to adjust the overtravel, as always make sure the gun is unloaded. Then you start turning the screw in a little at a time - about 1/2 turn - and then pull the trigger. If the hammer falls go another 1/2 turn, try the trigger again. Continue to do this only until the hammer will not fall when the trigger is pulled. Now turn the screw out about 1/4 turn and pull the trigger. Do this until the hammer falls.

You have now reached the point where the overtravel will just allow the sear to release the hammer, now turn the screw out 1 to 1 1/2 turns, this should give you sufficeint overtravel. Once you have the overtravel where you want it the screw should have a small amount of blue locktite applied.

I would also suggest that you completely disassemble the pistol including taking the grip off so you can inspect the parts. You need to inspect the hammer, sear and also make sure the trigger shoe is tight on the trigger bow.

If you are not comfortable with doing this I would strongly suggest taking it to a gunsmith or someone that is familiar with this type of pistol since mistakes in this area can result in a dangerous situation.

Hope this helps.