The truth on how centered a primer strike is on a revolver....

[ABPOS]

So..... I have 3 revolvers and I'm not necessarily a newb but I feel like I still have a lot to learn.

442, Colt DS, and a Model 19. So.. both of the snubbies seem to hit their primers off center. I have not really looked at the Model 19's real closely but I will next time I shoot it because I want to know what the deal is with this.

I've heard some people say it's normal for them to be off center. And then I hear other people say they shouldn't be off centered.

Can we have a discussion about this so I can learn?

Thanks.

 

[Jellybean]

How off centered are they? They can be a little off centered but they should be as close as possible. Inside the primer is an "anvil" which is closer to the primer cup in the middle and further away at the sides. When the firing pin hits the primer it causes the priming compound to be smashed against the anvil in order to make it explode. If the firing pin is too far off center, where the anvil is further away from the primer cup, it can cause misfires, or worse yet, the dreaded hangfire.

 

[steelslaver]

If the strike is off center top to bottom all is good. If it is off side to side you may have a timing issue.

 

[ABPOS]

Interesting. It would be hard to know but I guess if you looked at them right away while still in the cylinder, you could tell if it was up or down or side to side.....

 

[mike campbell]

Interesting. After 50 years of handgunning and sending tens of thousands of rounds downrange ... and witnessing tens of thousands sent downrange by others, I've never seen a discussion of this topic. I guess I can read and learn.

 

[deyomatic]

They're all better than this one, I hope...

 

[merl67]

They're all better than this one, I hope...

Wow ! That is a Colt. I have seen off centered firing pin strikes more on older Colts than Smith & Wesson revolvers, but none quite this bad definitely timing issues.

 

[ABPOS]

Interesting. After 50 years of handgunning and sending tens of thousands of rounds downrange ... and witnessing tens of thousands sent downrange by others, I've never seen a discussion of this topic. I guess I can read and learn.

Well it's not something that came up as an issue when I shot autos, but once I started wheelgunning a while back, it seems like it has raised some questions. People making comments etc. Just wanting to learn about what is customary.

From my 442 last range session, round didn't go bang. I ended up finding the hammer stud busted in my gun, but I've always wondered about the off center strikes....:

 

[Scharfschuetzer]

I've normally seen this in semi-autos and one of my 1911 Commercials strikes off center about the same as in the photo above. It has misfired on occasion with that off center strike.

While all my revolvers hit near center, I don't think but one or two are perfect in their strike. I've never had a misfire with any of my revolvers with near center strikes.

I've never really thought about it, but one of the first things I check with a new firearm at the range, rifle, pistol or shotgun, is how centered up the primer strike is. Very few are actually perfectly centered. It doesn't need to be an X, but as long as it's in the 10 ring, you're good to go.

 

[tops]

Interesting. It would be hard to know but I guess if you looked at them right away while still in the cylinder, you could tell if it was up or down or side to side.....

If shooting an auto loader you need to be quick. Larry

 

[mm93]

Both statements are true! They shouldn't be off center, but it's not uncommon for it to be found. As long as it doesn't result in any misifres, it should never be an issue.

 

[Jellybean]

As steelslaver mentioned timing issues can cause off centered strikes, as can cylinder axis issues, and there are also quality control matters. In standard production runs every firearm will not be perfect but will hopefully fall within an allowable range of tolerances.

If the weapon functions with no other fault than a consistent off center strike, there may be nothing to worry about. If you want to know for sure it's alright, or if there are other problems such as lead shaving, have someone that is familiar with the type of weapon take a look at it.

If your hits look like the one ABPOS pictured above, there is a problem as that is too far from center. Even if the gun is mechanically sound that strike is too far off to be reliable, especially for a defensive handgun.

 

[gwpercle]

Interesting. After 50 years of handgunning and sending tens of thousands of rounds downrange ... and witnessing tens of thousands sent downrange by others, I've never seen a discussion of this topic. I guess I can read and learn.

52 years and I've never seen , read or thought about it either .
As long as the primers ignite...I'm happy.
Being off dead center has never been an issue in my years of experience .

Gary

 

[Milton]

Well shucks,I'm in trouble ALL my .22's have off-center firing pins strikes!!

 

[rubiranch]

This isn't something I've ever paid any attention too but it got my curiosity up.

Here's the last 3 boxes of .357 that I shot recently. 50 rounds in my M-28-2, M-27 and my M-686. I don't know which box was fired in which gun.

It appears that the last box the gun seems to hit the center more than the others.

Next time I go shooting I'll take the same 3 guns and mark the boxes to see which one is better at hitting the center of the primer.

There were not any misfires.

 

[Black Sunshine]

From an engineering perspective, there exists a circle of some specific diameter within which a primer should ignite if struck with proper size/force/depth firing pin. I would expect SAAMI would control this.

Since there has to be clearance between moving parts and no part can be made perfect, there will be tolerance stack up. A gun designer would design such that all applicable clearances and tolerances result in a pin strike within the specified diameter (and probably leave margin, if possible).

That being said, some degree of eccentricity would be normal and expected.

 

[ABPOS]

Thanks for the pic rubiranch. I'll have to check my model 19 the next time I go. It's the only one I've not really inspected the strikes. I've not had a dud yet. But the two snubbies I've had. Definitely more like your first box shown and maybe worse.

 

[rubiranch]

Thanks for the pic rubiranch. I'll have to check my model 19 the next time I go. It's the only one I've not really inspected the strikes. I've not had a dud yet. But the two snubbies I've had. Definitely more like your first box shown and maybe worse.

I am really curious to which revolver hits the center with the most consistency.

Interesting.

 

[rubiranch]

Next time I go shooting I'll take the same 3 guns and mark the boxes to see which one is better at hitting the center of the primer.

I'm betting it is the 686 no dash that hits the primer dead center.

 

[ABPOS]

OK, so I put 70 rounds through a 637 and 20 through my model 19.

Model 19-2:

637-2:

The 637 hits look way better than my Colt DS and deeper than my 442 was showing last range session. I think a bit more centered than the 442 also......... So that part I'm happy about.