Powder or primer degradation

[DWier]

A friend sent this and is asking advice. (I'm interested as well).
22 Hornet. 2 cases, top right, have deep firing pin strikes. I am wanting to blame on degrading powder as these were loaded in 2008. Your thoughts?

WSR primers, small rifle; 10.6 grains IMR 4227, and a 40 grain PSP .223 Hornady bullet. Rifle a Model 43 Winchester, 70 years old.
Any ideas?

 

[crystalgayleguy]

what does the brass look like

 

[Stammster]

The picture is hard to see, but those look like pierced primers and not deep strikes.

Late 2008 was a rough year. Any chance of an overthrow or wrong powder? Primers look very flat also.

 

[Doom2]

Looks like flattened pierced primers to me. Check the bolt face!

 

[Stammster]

Are they all R&P brass? Can't tell with the blurry picture, but the head stamp also looks different.

 

[J E Custom]

Start with measuring the firing pin protrusion first. Measure the protrusion with the firing pin de- cocked. Some actions are hard to release the firing pin, so with a dowel or cleaning rod with a blunt jag, cock the firing pin and measure to the bolt/action face to the muzzle, with a washer and a pair of vice grips, (I use a locking collar on the rod flush with the muzzle) ,holding the rod against the action face with the washer, clamp the vice grips/ lock collar on the rod and clamp it to get the washer flat against the muzzle. Then snap the trigger releasing the firing pin without the rod against the firing pin, very carefully replace the rod back in the bore and using feeler gauges Measure the gap between the washer and the muzzle.

This is not very accurate, but it will tell you if your Firing pin protrusion is within the proper range. (I prefer .055 to .060 thousandths)

The best way to measure this is with a firing pin protrusion tool like this.

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If you find out that the firing pin is within spec. Then look for primer, powder and head space problems exist.

None of the primers look smashed/flattened from pressure so I suspect it is piercing from to much protrousion.

J E CUSTOM

 

[Jed Cooper]

I'm on the fence about this one. Overpressure and excessive pin protrusion??

 

[DWier]

Start with measuring the firing pin protrusion first. Measure the protrusion with the firing pin de- cocked. Some actions are hard to release the firing pin, so with a dowel or cleaning rod with a blunt jag, cock the firing pin and measure to the bolt/action face to the muzzle, with a washer and a pair of vice grips, (I use a locking collar on the rod flush with the muzzle) ,holding the rod against the action face with the washer, clamp the vice grips/ lock collar on the rod and clamp it to get the washer flat against the muzzle. Then snap the trigger releasing the firing pin without the rod against the firing pin, very carefully replace the rod back in the bore and using feeler gauges Measure the gap between the washer and the muzzle.

This is not very accurate, but it will tell you if your Firing pin protrusion is within the proper range. (I prefer .055 to .060 thousandths)

The best way to measure this is with a firing pin protrusion tool like this.

Shop All Shooting & Gunsmithing Supplies | Brownells Since 1939

Brownells offers Free Shipping over $49 through July on all products including ammunition, firearms, reloading, handgun and rifle parts, AR15 supplies, gun cleaning products, and more!

www.brownells.com

If you find out that the firing pin is within spec. Then look for primer, powder and head space problems exist.

None of the primers look smashed/flattened from pressure so I suspect it is piercing from to much protrousion.

J E CUSTOM

Thx. I'll pass it on and and let you know.

 

[Stammster]

I'm on the fence about this one. Overpressure and excessive pin protrusion??

I'm not seeing excessive pin protrusion on the others with rounded primers. I shot a box of factory 22 hornet out of my 43 last week and they looked exactly like all those in the picture (except top 2 right).

IMO pin protrusion theory is a red herring.
Also I'm not buying degradation of the primer or powder unless those rounds were stored at some extreme high temperatures. If so, then why only 2 out of the lot? I shoot loads 20, 30, 40+ years old all the time. 12 years is nothing, unless the powder was really old at the time of loading. And if so, why aren't all the rounds seeing issues.

My bet is overpressure either a.). overcharge for given case capacity or b.) wrong powder or c.) wrong seating depth/jammed bullet on those 2 bullets - in that order.

If your friend has some unfired, measure COAL for consistency, pull the bullet / weigh the charge, and visually inspect the powder. Also verify head stamp.

With these small cases like the 22 Hornet, a 1/2 grain overthrow is huge, as is case capacity with different brands of brass.

 

[DWier]

I'm not seeing excessive pin protrusion on the others with rounded primers. I shot a box of factory 22 hornet out of my 43 last week and they looked exactly like all those in the picture (except top 2 right).

IMO pin protrusion theory is a red herring.
Also I'm not buying degradation of the primer or powder unless those rounds were stored at some extreme high temperatures. If so, then why only 2 out of the lot? I shoot loads 20, 30, 40+ years old all the time. 12 years is nothing, unless the powder was really old at the time of loading. And if so, why aren't all the rounds seeing issues.

My bet is overpressure either a.). overcharge for given case capacity or b.) wrong powder or c.) wrong seating depth/jammed bullet on those 2 bullets - in that order.

If your friend has some unfired, measure COAL for consistency, pull the bullet / weigh the charge, and visually inspect the powder. Also verify head stamp.

With these small cases like the 22 Hornet, a 1/2 grain overthrow is huge, as is case capacity with different brands of brass.

Thx for the advice. I'll let him know and report back. Appreciate everyone's opinion and advice

 

[Stammster]

Actually in looking up the load, Nosler has a 10.6 gr load of 4227 on the mild side and 12 gr as max.

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Both being compressed, with 12 gr at 121%. So I'm not so sure on my overthrow theory now being the front runner for the overpressure.

 

[del2les]

Either wrong powder charge
Wrong bullet weight
Accidentally loaded a couple of small pistol primers*
* I have seen a few loaders make this mistake with small and large primers, pistol instead of rifle primers. One guy grabbed the wrong primer box and loaded a full box this way. The first couple of rounds were blowing gas around his firing pin and out the bolt right into his face. Another guy forgot he had 2-3 pistol primers left in his auto primer then put a box of rifles in there

 

[wv270wsm]

Does he by chance use a powder dispenser like a charge master or lymans version. I screwed up a few years ago and forgot to clean out the dispensers tube . Luckily as soon as I went to get a pan full of what should have been w748 it came out an imr powder. It could happen and I'm sure it has .

 

[FURMAN]

I don't have a lot of experience with that case capacity but I did have a 17 HH that pierced primers often with lil gun. With a small capacity like that certain powders are more prone to pressure swings. I know nothing of IMR 4227 but I would consider a powder like H110.