Dry-Fire Mechanical Trivia

[Guest Lester Weevils]

How about a thread on the mechanical trivia of various ways dry-fire can bung up various guns?

 

Haven't done a google search to see if there is such a thread on other gun forums, but there doesn't appear to be one here, at least recently.

 

On .22, supposedly some models will damage the firing pin when it over-extends and slams into the edge of the chamber. At least one .22 revolver manufacturer warns that dry-fire will bung up the edge of the cylinder holes.

 

On at least one kel-tec pistol, supposedly dry-fire slams the firing pin against the extractor spring screw, which bungs up the exposed screw threads making it difficult to remove the screw and possibly messing up the threads in the slide if you do manage to remove that screw.

 

Think I recall warnings that on some centerfire guns, the firing pin over-extends which will tend to weaken the firing pin spring, but perhaps I'm recalling that detail wrong.

 

It just seems interesting to know sundry details of exactly HOW dry fire messes up the various models of gun which can be damaged by dry-fire.

 

=====

 

Another interesting thing would be the best ways to make one's own snap caps, or alternate ways to safely dry-fire. One fellow cuts a small bit of clear plastic tubing and wedges it down behind the back of the firing pin on a CZ, so the hammer hits the plastic tubing rather than the firing pin.

 

I have made centerfire snap caps by taking a de-primed case and filling the primer pocket with silicone sealer, with a slight "dome" of silicone extending above the case bottom. The silicone survives quite a bit of dry firing before it gets chewed up, but I don't know if such an ersatz snap cap is "too hard" or "too soft". Or even if it really matters much. Maybe it would depend on the specifics of the dry-fire failure mode in each gun so affected?

 

Presumably the commercial spring-loaded snap caps are "fit for the purpose" but dunno even if that is true. Maybe they could be "too hard" or "too soft" to be ideal in some guns?

 

Have thought about possibly silly overkill of gluing a little disc of foam, topped by a little disc of brass into the primer pocket. Or perhaps just filling the primer pocket with silicone sealer and topping it with a little disc of brass or hard plastic, in hopes of making a more durable homemade snap cap than simple silicone alone. An impact surface hard enough not to get dinged up, but with a little "give" in case metal fatigue of the firing pin hitting something too hard would tend to break the firing pin.

 

Just a fired .22 case might suffice for a .22 snap cap, but I wonder if repeatedly firing on the same dent in the brass would be ideal? Maybe just keeping the firing pin from impacting the edge of the chamber is "good enough" but repeatedly hitting a previous "dent" in the brass wouldn't be exactly the same as the firing pin making a new dent every time?

 

Perhaps there is a resilient plastic with similar rockwell hardness to cartridge brass, which would "give" on impact but "spring back" after being struck, so it would take a long time to wear a dent in the plastic snap cap? Make a few plastic .22 dummies on a mini-lathe. Nylon? UHMW?

Edited January 4, 2013 by Lester Weevils

[DWARREN123]

I believe that too much dry firing can also damage the breach face, on some firearms,  to the point of causing it to break or crack from the firing pin hitting it.

[LngRngShtr]

I always toss an empty in just in case. used to decap and fill primer pocket with hot melt glue or a piece of pencil eraser.

 

especially on O/U S/S shotguns as the standard belief is fragile firing pins besides I dont want to explain to my Dad how I broke the Family's Parker firing pins

 

All except my Browning Medalist   gotta love the onboard dryfire setting   :rock:

 

John

[chances R]

Most modern firearms, other than rimfire can be dry-practiced almost endlessly.  I know multiple instructors that have done this with 1911, Glock, M&P, and XDs thousands of times with no problems other than general wear and tear.  If there is an issue it should be a simple repair.  Which do you think causes more wear, firing a gun 5,000 times, or simply dry practice for the same number?

[Guest Lester Weevils]

I believe that too much dry firing can also damage the breach face, on some firearms,  to the point of causing it to break or crack from the firing pin hitting it.

 

Thanks, another failure mode for the list.

 

I always toss an empty in just in case. used to decap and fill primer pocket with hot melt glue or a piece of pencil eraser.

 

especially on O/U S/S shotguns as the standard belief is fragile firing pins besides I dont want to explain to my Dad how I broke the Family's Parker firing pins

 

All except my Browning Medalist   gotta love the onboard dryfire setting   :rock:

 

John

 

Pencil eraser and hot melt both sound good, thanks.

 

Most modern firearms, other than rimfire can be dry-practiced almost endlessly.  I know multiple instructors that have done this with 1911, Glock, M&P, and XDs thousands of times with no problems other than general wear and tear.  If there is an issue it should be a simple repair.  Which do you think causes more wear, firing a gun 5,000 times, or simply dry practice for the same number?

 

A possible informational problem-- The people who write the manuals might be guilty of using too much boilerplate when composing the instructions. Like the tool manuals that warn to always wear safety glasses when using a micrometer or caliper or even rechargeable batteries, because the company puts the safety glasses paragraph in every manual they print. I'd have to look back to confirm, but am pretty sure that the dry-fire warning is in the manual of lots of my guns, that theoretically ought not be hurt by dry-firing. So how does one know for sure, in some cases? 

Edited January 4, 2013 by Lester Weevils

[chances R]

IMO the liklihood of having an ND, or, a 'click' because a snap cap is loaded instead of a live round out-weighs the potential for damage.  It is certainly a legimate purpose of the gun to dry practice, and therefore anticipated wear and tear in the training process.  If it makes one feel better to use a dummy device, nothing wrong with it, but I have seen both of the situations mentioned happen with shotguns, and have heard of same with pistols.

[DaveTN]

Mechanical Engineering, Metallurgy and Physics tells me dry firing is not good. The internet tells me it is Okay. Choices, Choices.....

:)

[chances R]

Mechanical Engineering, Metallurgy and Physics tells me dry firing is not good. The internet tells me it is Okay. Choices, Choices.....

:)

Well there you go........you know if it is on the internet it has to be true  :cool:

[Guest Keal G Seo]

So I have always been told and practiced not dry firing rim fire while center fire is ok. As for the physics of it, it is pretty obvious why we shouldn't dry fire rim fire. But why do we hear that dry firing center fire is ok? Well my theory is that, besides it not striking the edge of the chamber, the weight of the firing pin (especially titanium ones) is so low that it won't damage the rear of the breech face. Energy = mass x speed. I mean look at the forces the firearm is built to withstand in that area and compare how little force the firing pin spring and weight of the firing pin actually impose. Now on the mention of a Kel-Tec over extending and hitting another component I can see how that might cause some damage, but in general I still dry fire center fire.

[DaveTN]

But why do we hear that dry firing center fire is ok?

Marketing. I was talking with a Gunsmith for one of the large gun companies and ask why they say its okay to dry fire when they know it isn’t. He told me that he doesn’t say it’s okay. He said he responds with, “If you damage your gun dry firing it; we will fix it free of charge.” He said that one of the gun companies was saying it’s oaky to dry fire their guns; so everyone else had to get in line or have it used against them.

Well my theory is that, besides it not striking the edge of the chamber, the weight of the firing pin (especially titanium ones) is so low that it won't damage the rear of the breech face. Energy = mass x speed. I mean look at the forces the firearm is built to withstand in that area and compare how little force the firing pin spring and weight of the firing pin actually impose.

So you have applied mass X speed (Physics) and now have a number you can use from your experience in Metallurgy and Mechanical Engineering to determine that number represents a force that the firearm and its materials were built to withstand. If your formula and all your data are good; you are good to go. Facts are tough to argue with.

[Guest Lester Weevils]

The Ruger GP-100 manual says "The GP100 revolver can be dry-fired without damage to the firing pin or internal components." Maybe that is "one of the gun companies" referenced by DaveTN.

 

I need to find time to go thru all my manuals and count how many say "do" versus "don't". Memory has the impression that most of em say "don't" but might be remembering wrong.

[Oh Shoot]

The Ruger GP-100 manual says "The GP100 revolver can be dry-fired without damage to the firing pin or internal components." Maybe that is "one of the gun companies" referenced by DaveTN.

 

If you look through the various FAQ sections at Ruger site, they state that every firearm they make is safe to dry fire.

 

Some "users" claim that XD striker retainer roll pin will break with enough dry firing. Springfield has never said anything about it one way or the other, though the manual suggests familiarizing yourself with the gun by operating it without ammo, including dry firing.

 

- OS

Edited January 6, 2013 by Oh Shoot

[LagerHead]

If you look through the various FAQ sections at Ruger site, they state that every firearm they make is safe to dry fire.

 

Some "users" claim that XD striker retainer roll pin will break with enough dry firing. Springfield has never said anything about it one way or the other, though the manual suggests familiarizing yourself with the gun by operating it without ammo, including dry firing.

 

- OS

 

I have heard that as well. I bought a heavy duty roll pin just in case. No way this thing is going to break.

 

http://shop.powderriverprecision.net/product.sc?productId=32&categoryId=4

[Clod Stomper]

In general, .22s shouldn't be dry-fired.  I've seen the results on a S&W .22 LR pistol.  The breech was peened and needed to be re-reamed.  I've never seen such damage on any Ruger .22.  Even after being dry-fired hundreds or thousands of times.  They design it so that the firing pin doesn't reach the breech face.

 

CZ-52s shouldn't be dry-fired.  Though I have one, I haven't dry-fired it.  I've always read that the firing pins are more brittle than modern guns.  I'm not willing to test it, lest I have to buy a new firing pin.  They used to be fairly easy to find, but I don't know about the present situation.

 

The manual for the Taurus PT-92/99 (from the '90s) says not to dry-fire.  It has been a few times without obvious damage, but the manual says no, so I don't do it.

 

Others that I have dry-fired hundreds to thousands of times without obvious damage:  Various 1911s.  AR-style rifles.  Glocks.  Colt-style single action revolvers and Ruger-style single-action revolvers.  Marlin lever-action rifles.  Savage 99 rifles.  Mauser rifles (excepting '89-'91-based rifles.  Don't dry-fire those.).  Mosin-Nagant rifles.  Lee-Enfield rifles.  M-14-style rifles.  Ruger Mini-14/30 rifles.  Various (modern) Remchester and Winington rifles.

 

Do some research.  If you hear that you should not dry-fire that particular model (or if it's a rimfire), do not dry-fire it.  Otherwise, don't worry about it.