ive never cycled a full mag through my Bushym4 (just pulling on charging handle, letting go and ejecting rounds to see if the magazine works fine) and i did so about ten minutes ago. the magazine worked fine, ejecting and loading rounds as i pulled (30 rds no problem). i started to put the rounds back in the mag when i noticed the primers all had dimples in them. i was a little worried. could the rounds have gone off? the gun was on safe as i was going through the cycle. but should the firing pin have dimpled the primers? is this something i should worry about and fix? is it a headspace problem?   AR gurus.....HELP !!

AR firing pin is free-floating and yes dimples are normal.

Yes, rifle can go off if conditions are right which is why "Pointing rifle in a safe direction" is an important safety rule

Mike

That's why most firing pins are made of titanium.  It's very hard, but also lightweight, so there's less mass, and when the bolt comes forward after being fired the momentum of the firing pin probably won't be enough to detonate the firing cap, but may dimple it.  I don't think it's anything to worry about.  It takes more than a dimple to detonate the firing cap.

Quoted: That's why most firing pins are made of titanium.  It's very hard, but also lightweight, so there's less mass, and when the bolt comes forward after being fired the momentum of the firing pin probably won't be enough to detonate the firing cap, but may dimple it.  I don't think it's anything to worry about.  It takes more than a dimple to detonate the firing cap.

Unless you've replaced your firing pin w/ a Titanium one, no stock mil-spec AR (that I know of) comes w/ a titanium firing pin installed. And as any long time reloader might attest to making sure primers are properly seated is a real item to check when reloading for a rifle such as the AR.

Mike

Unless you've replaced your firing pin w/ a Titanium one, no stock mil-spec AR (that I know of) comes w/ a titanium firing pin installed. And as any long time reloader might attest to making sure primers are properly seated is a real item to check when reloading for a rifle such as the AR.

The AR-15 I got came with a titanium firing pin.  At least I THINK it's titanium.  It's lightweight, and I absolutely can not scratch it with anything.  I've used a hard steel screw, a knife, concrete, and other things, and I can't put any visible scratch on it.

Speaking of which, are titanium firing pins really titanium, or are they some kind of titanium alloy, or something coated with titanium?  I thought I heard somewhere theat they aren't pure titanium or something like that.

Sorry to say, but I doubt it's titanium, it's more than likely a stock firing pin. I install a titanium in my Colt long range AR, it weighed 43% less that the one which came in the rifle (new), which weighted several grams less than mil-spec replacement pins or the pin in my stock Bushmaster.

Read about this subject here: www.fulton-armory.com/SlamFire3.htm

That's why they cost 30-60 bucks, and why most folk don't have them (they don't come as standard equipment on mil-spec ARs).

Mike

Follow the rules of firearm safety.  The dimpling is normal.  I still use steel firing pins, and I'm not about to change.   I have fired tens of thousands of rounds in both M-16's and AR-15's(ammunition: military, factory and my reloads).  I never had a misfire.  This doesn't mean it can't happen.  So, like Mr. Wilson, I will say keep the rifle pointed in a safe direction. Be safe and have fun!!!

Then why is it much harder than the hardest steel I can find?  I don't know of any other metal that's that hard.

Another good reason to keep different primers seperated. Pistol primers could be set off by this.

For what you were doing, you could have removed the firing pin.

Quoted: For what you were doing, you could have removed the firing pin.

Not so fast...  The cam pin rotates around / slides along the firing pin.  Without the firing pin in place, there is nothing to keep the cam pin from falling out of the bolt carrier and causing one hell of a jam.

Quoted: Then why is it much harder than the hardest steel I can find?  I don't know of any other metal that's that hard.

I believe its chrome plated.

I’m not so sure that titanium is all that hard.  I know that titanium hammers and sears used in custom 1911’s wear out faster than than steel ones.

i don't know if you could make a fireing pin from "pure" Titanium, i think it is too flexable. it is mix into aloy becaue it gives strength to softer metals

i heard this somewhere, correct me if im wrong

Most of us who handload use the Remington #7 1/2 primer with the .223/5.56 round. One of the reasons Remington brought out this "special" primer with the odd colored metal, was specifically because  the primer cup is a thicker metal than the stock small rifle primer.  I've certainly used other primers in the .223 (CCI small magnum rifle comes to mind), but all in all I prefer the Remington.  My understanding is that one of the specs for all commercial and military .223/5.56 ammo is that the primer cup be thick enough to not cause primer ignition from firing pin stroke during loading.


NOTE: While typing this response, MY ANTI VIRAL PROGRAM JUST KICKED IN TO  TELL ME I'D BEEN INFECTED WITH KLEZ.  SOMEONE OF YOU WHO RESPONDED AHEAD OF ME HAS THE KLEZ VIRUS.  Y'ALL BEST CHECK YOUR SYSTEMS.

Quoted: NOTE: While typing this response, MY ANTI VIRAL PROGRAM JUST KICKED IN TO  TELL ME I'D BEEN INFECTED WITH KLEZ.  SOMEONE OF YOU WHO RESPONDED AHEAD OF ME HAS THE KLEZ VIRUS.  Y'ALL BEST CHECK YOUR SYSTEMS.

It's not the forum. You got infected by opening an email and/or running an email attachment.

Quoted: Quoted: NOTE: While typing this response, MY ANTI VIRAL PROGRAM JUST KICKED IN TO  TELL ME I'D BEEN INFECTED WITH KLEZ.  SOMEONE OF YOU WHO RESPONDED AHEAD OF ME HAS THE KLEZ VIRUS.  Y'ALL BEST CHECK YOUR SYSTEMS. It's not the forum. You got infected by opening an email and/or running an email attachment.

Shamayim;
We went through all this with you on one of your posts last week. Either you didn't get your PC cleaned up properly last week, or you got another email like bOne said.

WRONG  WRONG  WRONG

I HAD JUST HAD THE PROGRAM TELL ME THAT MY MACHINE WAS CLEAN,  I HAD NOT RECIEVED NOR HAD ANY E MAILS  AND THE PROGRAM KICKED IN WHILE I WAS IN THE MIDDLE OF TYPING UP THE RESPONSE.  YOU GUYS DON'T KNOW WHAT YOU THINK YOU KNOW ABOUT THIS VIRUS

primer cups are made of brass, but most are nickelplated to give it the silver color.  Remington, however, has long kept it unplated, and recently, Winchester has done the same.  It is normal to see minor primer dimpling when cycling the bolt, no big deal.  Titanium FP for the AR are a nice scam--the tips wear faster then steel, cost ALOT more, and unlike bolt guns, doesn't change the lock time much as the slowest part in the action is due to the parts in the lower receiver (ie the hammer, etc).  Bolt guns don't generally use a hammer, and a titanium FP in a striker type mechanism can be slightly faster.  If the Ti FP actually does decrease lock time or enhance function, I'd  think you would see the serious target shooters, etc. use it--well, they don't.  
As the folks have already mentioned, just keep the muzzle safe when you cycle the mag just in case, and save your money with the standard FP.  

Quoted: WRONG  WRONG  WRONG I HAD JUST HAD THE PROGRAM TELL ME THAT MY MACHINE WAS CLEAN,  I HAD NOT RECIEVED NOR HAD ANY E MAILS  AND THE PROGRAM KICKED IN WHILE I WAS IN THE MIDDLE OF TYPING UP THE RESPONSE.  YOU GUYS DON'T KNOW WHAT YOU THINK YOU KNOW ABOUT THIS VIRUS

Shamayim - was your Outlook mail program open at the same time?  If so, you might have received an infected e-mail that your e-mail program promptly deleted.

You aren't going to get the Klez worm by looking at a web page.

the_reject

Quoted: Then why is it much harder than the hardest steel I can find?  I don't know of any other metal that's that hard.

Titanium is not hard.  Most titanium alloys are impossible to harden.  The ones that will harden don;t get much harder than the low end of the Rockwell scale.

The primary properties of titanium alloys are good wear resistance, heat resistance, and a high strength to weight ratio.

Strength to weight ratio is tricky though.

Titanium alloys are stronger than steel BY WEIGHT, but weaker by volume. Titanium is a low density metal, so to achieve comparable strength to a steel part, a titanium part would have greater volume but lower weight/mass.  Aluminum is the more apropo comparison.  Ti is much stronger than aluminum by mass and volume, but also denser.  So in some cases some of the advantages are lost because part volume must remain stable, so while the change to titanium increases strength, the part volume remains the same and the denser titanium ups the mass of the part as compared to a similar aluminum part.

In a firing pin, volume is set by the design of the firing pin and the design of the bolt.  So a titanium firing pin is lighter, but also weaker, nor as hard.  You could TiN coat the firing pin...that's HARD, but you wouldn't do that over titanium, but rather over steel.  TiN is used to reduce wear on cutting tools mostly.

Most likely you have a hard chromed steel firing pin.  That's good. It'll resist corrosion and wear better than plain high speed steel.

Quoted: Quoted: For what you were doing, you could have removed the firing pin. Not so fast...  The cam pin rotates around / slides along the firing pin.  Without the firing pin in place, there is nothing to keep the cam pin from falling out of the bolt carrier and causing one hell of a jam.

Not so fast...This has happend to me exactly never, and it sure as hell beats an ND.  If it did bind up, you would know why.  Here's a solution.  Cut down a firing pin so it holds the cam pin in place, but can't protrude through the bolt face.

I picked up this knwledge about al, ti, and steel in am magazine article about conecting rods, I have forgoten the exact percentages, but you will get the idea. According to the article Al is a lot lighter than Ti or steel, but it wears out 10x faster than quality steel. Ti was somewere between 75-80% the weight of steel, but it still did not have the durability of steel. I just had a pure Ti rod pulled out of my lower leg, and I was very dissapointed with the weight. I realize that it is much lighter than the steel equivalent, but the thing is still a big pice of metal and therefore weighty. It was also scratched in several places where the tools used to remove it where inserted. I am not sure if I helped unless anyone was contemplating a connecting rid purchase, but you get the idea.  

It might be normal to see the dimple, but I have seen numerous slam fires on the highpower range. I don't chamber rounds in semi-autos anymore in my home, and neither should you. If you do, at least don't point the rifle at the wife, the TV, the kids, the computer or the dog!