What causes hang-fires?

[Mikecr]

On bolt misalignment, first you should disassemble the bolt and pay mind to the causes of it.
You'll notice that the striker can & will release with the bolt turned plus xdegrees to minus ydegrees, and that in each case energy is lost. Often the piece that rides up the cocking ramp, strikes the cocking ramp on release if the bolt isn't turned far enough, driving the bolt handle downward(along with your muzzle velocity). If the bolt is overturned there is friction against a cocking piece side, and on the striker's near-full travel the bolt handle twitches upward(and again MV drops).
The sear section of the cocking piece also drags within it's action slot under the shroud.
Some bolt actions are better than others in this regard, but my guess is that they ALL do it(including aftermarket actions).
It's one of many flaws in todays standard design.
Cycle & dry fire your action repeatedly while watching the bolt and shroud. You'll see alot of ugly movements going on each time differently...

The only fix is to remove all the slack at the rear bolt, and make the bolt turn index to perfect alignment everytime using alignment pins(if needed), a stop, or ball detents.
These same actions can center the rear of the bolt and lightly preload lugs.

But anyway, I think the powder load/temps were the biggest contributor to your hangfires.

 

[Airgunner7]

Well, I got the bolt apart and am cleaning it.

I started to notice 50% hangfires last summer on a hot day and same now that it is cold so I am hoping it is just a cleaning issue. I'll start paying attention to the bolt position (tight up down or somewhere in the middle)when shooting if it continues. Still have 45 rounds before exploring a new primer.
Thanks for the great info.
BTW is .052-.056 ok for firing pin?

 

[Airgunner7]

Had a few rounds with different primers, same load, same problem...low flying hangfires....even had one of my regular rounds not go off. Pin not hitting hard enough? Bad Retumbo? Very frustrating.

 

[Airgunner7]

Bought a box of factory ammo to see if it is the rifle or the reloads. 54 bucks for 20 shots...ouch.

 

[devildogandboy]

where do you store your powder and primers? are they in an controlled environment where it is dry and cool all the time?
i had one incident in my life back about 33 years ago, (yes i am probably older than most of you) where i reloaded a batch of 357 magnums that didn't fire or were hang-fires. turned out they were stored in the house in the laundry room where the moisture content is always higher!
bad primers or bad powder, it corrected itself once i got new components and was relieved to know i had no problems with the firearm at all. this same scenario would apply to handguns as well as long-guns.
i have never had this happen to me again since i placed all items in an area where it is DRY AND COOL!!
just a thought IMHO that might help someone. (been rolling my own since '72)

 

[Airgunner7]

Well, I use a dry box and the powder is in plastic bottles...who knows.

 

[Airgunner7]

Went out to shoot the 7 rum again. I tried several different ideas...
-same load-same hangfires (still have 20 more of the 50 loaded)
-seated bullet deeper for less case volume-same hangfires (even one full dud)
-same load on virgin brass loaded different time-some hangfires
-factory Remington rounds-Flawless....so it's not the rifle

Bad/weak primers (cci 250) or bad Retumbo powder.

Think I'll work up a load with some Federal 215M primers and see what happens before I buy new powder.

 

[Airgunner7]

Problem solved....hang fires gone and velocity back up.

Tried Fed215m primers. Must have been a contaminated lot of cci 250 primers or just not strong enough to light 85-86g of retumbo.