Hornet headspace thoughts

[Nobade]

The other post regarding the Savage 40 to K hornet rechamber got me thinking about this. Has anyone here ever seen a factory made Hornet rifle with proper headspace? I never have, and I've looked at hundereds of them in all shapes and flavors. The rim on a Hornet case is nominally about .062 inch. Most Hornet guns run about .069-.075. It's no wonder the little Hornet has such a bad reputation for short case life and poor accuracy, it doesn't have a chance in guns like this! I own a Contender with a 10 inch factory barrel chambered for the Hornet. I've shot it for about 12 years now, and finally decided I'd had enough of cases breaking in half. The rim cut in the barrel was .068" deep, and there is .004" clearance between the barrel and the standing breech. No wonder it is hard on brass with .010" headspace! I took a tip from the shotgun guys - I turned a little steel ring and soldered it into the rim cut. Then I went in with a Hornet reamer and cut it so the rim recess was .060" deep, and properly polished the chamber.  I now have only .002" headspace. So what happened? Groups with the same loads are approximately half of what they were, and I haven't had any cases break. I can run loads considerably hotter and the cases fall out instead of being hard to extract. This is what TC should have made in the first place! If anybody wants to test the headspace on their Hornet chambered gun, just full length size a case, prime it, and fire the primer without any powder or bullet. If the primer is flush with the case afterward, congratulations! You've got a really rare gun. If it's sticking up, that's the amount of excess headspace you have. If your cases break in two frequently, you now know the answer why.

[gunnut69]

Your right there!! I quite full length sizing a long time ago, especially with the Hornet.. Brass lasts a lot longer and they shoot better. The first loading is a little iffy but they are OK for shooting practice.. Your cure would be the best certainly but the case would still 'grow' to fill the chamber. So case life shouldn't be helped, should it??  I guess I'm confused..

[iiranger]

When I was young I started reading Jack O'Connor's columns in Outdoor life and this was mentioned many times as the reason for the K Hornet. You put a shoulder on to headspace on and it all disappears... b). later I came to realize, that the Hornet is just the .22 WCF, a black powder cartridge of about .22 High Velocity performance, with smokeless and a jacked bullet. Occassionally there was a mention of the owner of a .22 WCF shooting Hornet ammo and the jacketed bullet wearing the rifling out of the softer steel barrel from the black powder era. Brass strength and pressure levels are held to this level of performance too... luck

[RonF]

Gunnut, what causes the difference in case life is this:  With excessive headspace, the firing pin drives the case forward, it fires and the pressure causes the case walls to grip the chamber, but the head doesn't expand and doesn't grip anything, so it can move back.  When it does, it stretches the brass just ahead of the case head and we get a separation.  It may happen after two firings or more, but it happens.  When headspace is right the growth occurs in the forward area of the case, which is thin and softer, so it doesn't break.  Does this help?

RonF

[gunnut69]

I suppose but I've reloaded some hornet brass many times with excellant results. The key is partial sizing in my opinion. This negates the repeated sizing which leads to the eventual seperation. I've not checked the headspace on any of my hornets but now I guess my curiosity will make me.. In my esxperisnce the folks who've had real seperation issues with the hornet were trying to make it into a 222. Of course the KHornet's main purpose was to inprove brass life so this is a valid discussion. Perhaps the KHornet would not be needed if headspace were tightened..

[StrawHat]

Partial full length sizing is what worked in my 22 WCF.

I ran the brass into the FL die until most of the neck was sized.  Everything else was as it came from the chamber.  After 8 or so loads they started to get tough to chamber in my single shot so next time at the bench the FL die got screwed in a little at a time until the case would chamber in the rifle with just a hint of resistance.  Then the die stayed at that setting until I gave up on getting that rifle to shoot with black powder and lead.

Looking back, the blame would have to fall on me not the gun.  One of these days I may start that project again.

Try partial sizing before giving up on the Hornet.

[Nobade]

This is my whole point. Yes, partial resizing (I use a Lee collett die) helps. But the cases will still break in half if the headspace is excessive because the hornet's shoulder will not maintain headspace against the force of the primer. The question remains, why are firearms chambered for the hornet made with excessive headspace? BTW, I just got two brand new Ruger 77 hornet rifles in to be rechambered to K hornet. I checked, and sure enough both of them have more than .010 excessive headspace. The brass will not break if the guns were made correctly. 

[gunnut69]

Nobade-- I had always blamed the short case life on thin brass and never checked the headspacing on the rifles.. You may have a point but you've made more work for me.. I'll have to check, just to know..

[alan in ga]

You are right. Hornets are poorly 'rim spaced'.
I've built several 17 Ackley Hornets. Cutting the rim space [headspace] was a high priority when chambering. I measured several batchs of new Hornet case rims as I wanted the thickest to be able to chamber if it was not 'too' far out of the norm for what rims measured.
A friend has a GO headspace gauge he purchased for using when chambering our new 17 Ackley Hornets. It is a "shoulder" headspace gauge. I let him know it was worthless to me,,as the chamber will be what it will be after fireforming the new die formed 17AH case. However the rim is what I always rely on for FIRST fireforming headspacing.
When I made my 17AH barrels, I cut a NEW Hornet case in half. Then I could use the rim end to check "rim space" when cutting the new 17AH chamber.
I also consider rim thickness when chambering an existing chamber in 30/30,,,to 30/30 Ack Improved. Same thing,,poor oversized rim relief.
Yup,,the FIRST shot counts when firing brass. You can do several things to help control headspace after fireforming,,,but I want to do it RIGHT on the FIRST shot, too!
You know it.
Alan in GA.

[coyotejoe]

  Back in the seventies I bought one of the Uberti baby rolling blocks in 22 Hornet. It had excessive headspace and cases separated, some on the first firing, none lasted more than three loadings, starting with new unfired brass. Accuracy was also terrible, best groups ran three MOA and most loads were worse. I got it rechamberd to 218 bee, with proper headspace and got sub MOA groups from the same barrel and never wore out a case after many many reloadings. Neck sizing may help extend case life but the case is greatly weakened by the first firing with excessive headspace. One could start with unfired brass, open the neck with a .257" expander, then resize the neck just enough to chamber and thus have good fireformed brass. Whether the sloping shoulder of the Hornet case would then maintain headspace I don't know. The .218 Bee is a better cartridge in every way, it will do anything the Hornet will do and just a bit more the Hornet can't hope to do, especially with bullets of 50 grains or more.

[alsaqr]

No doubt  many .22 Hornets are manufactured with excessive head space.  Full length re-sizing can ruin .22 Hornet case life.  The .22 Hornet is a high pressure cartridge:  Some .22 Hornet guns, notably the rolling blocks and the Winchester bolt action Model 43, soon develop head space problems on their own.  The Model 43 is notorious for since it has an updated .22 rim fire action.