I have just started shooting a .22 hornet. The load I am using is 12.5 grains Lil Gun, CCI 400 primer and Nosler 45 grain Hornet bullets. So nothing too remarkable there. It shoots fine, but I am getting pressure signs (maybe!). The primers are cratering. They aren't fllattened and there are no other pressure signs. I have used the same lot of primers in .222 rem loads, and no problem. I am wondering if maybe the reason for the cratering is that the firing pin strikes a little weakly (gun is 35 years old), so part of the rounded end of the pin is still inside the bolt face, allowing a larger arear for the primer cup to flow into. There's a picture below (sorry, it's a bit big - but I wanted clear detail).

Give me your comments - should I be worried?

Tell us more about what you are shooting. I know that some European barrels for the Hornet are very, very tight. I don't recall offhand what diameter Nosler makes their Hornet bullets. If you are shooting .224 diameter bullets, going to .222 diameter may be part of the answer.

I know that Herter's brought some Hornets into the states from Europe that were so tight as to be dangerous about 35 years ago. Slug your barrel and find out what you have.

I started to say that you have an oversized firing pin hole until I got to the bottom row of cartridges. The second from the left on the bottom shows clear signs that the primer is not only flowing into the firing pin hole but flowing to the edges of the primer pocket as well. That would bother me. The last two in the bottom row seem to show little tits on the rim where brass started to flow into the extractor cut. If that is not merely a trick of the light in the photo, it is THE classic warning sign of dangerously high pressure.

Leftoverdj,

Thanks for a thoughtful reply. The rifle in question is a BRNO ZKW465. I know others who shoot these and they have had no problems. I will however slug the barrel just to confirm bore size.

The brass flow you observe is, I think, a trick of the light in the picture. I have seen this phenomenon before - though not from any load I ever made - and would recognise it easily. I certainly would stop shooting immediately if I saw that symptom of overpressure. Also, bolt lift was no harder than when chambering the round. As for firing pin fit, I have examined that too, and it's OK. What puzzled me about this is that the primers are not unduly flattened yet I have cratering. I would expect them to be well flattened before cratering started, hence my assumption that the pin was not getting far enough out, leaving a larger gap which the primer cup could easily expand into.

My next thought is to try some factory loads and see if they exhibit the same signs. If so, I think that leaves me with either my original assumption, or a tight bore. I don't really see any other possibilities. I will check the bore before any further firing.

The Noslers are .224. I do also have some .223 Sierras which I can try if the bore diameter turns out to be the problem.

Any other thoughts from you?

Patrick

Hey Patrick, When you shoot the Factory ammo, measure the Pressure Ring Expansion(PRE) on the spent cases with a 0.0001" capable Micrometer. The PRE is found as the widest diameter ahead of the rim.

Rotate the case between the anvils of the Micrometer until it hangs and that will be the high spot which you will need to record on a piece of paper.

After you shoot the box of Factory Ammo and take the PRE measurements, do an "Average PRE" and consider that the SAFE MAX for those cases.

Full Length Resize the Factory Cases then reload 3 of them with 11.0gr of the Lil'Gun. Shoot and measure the PRE. Increase the charge in 0.2gr increments until your Reloads match the "Average PRE", and you have matched the same Pressure level as the Factory Ammo.

Leftoverdj may be correct about the "Bore Diameter" being different. I don't know anything about BRNO rifles, so I won't speculate on that.

By the way, 0.001" Calipers are not accurate enough to do these measurements. You can use the 0.0001" capable Micrometer on ALL cartridges to attain a SAFE MAX, so it is a good investment.

Best of luck to you.

I think you are ahead of me. Trying factory loads surely the next step.

There are some rather remote possibilities that occur to me. You might check the size of the flash hole in the cases. You should certainly try another primer. You might also try reseating a couple of those fired primers. I am thinking that if the primers are a bit short or the pockets a bit deep, they would have a few thous running room and that just might possibly produce those symptoms. A stronger firing pin spring could not hurt anything either.

The only time I have seen those symptoms was in an old Savage in .25-20. Both the hole and the firing pin were grossly oversized by current standards. I bushed the hole and reduced the diameter of the firing pin and shoot it happily to this day.

I have a BRNO ZKW465 and have no pressure problems with max loads using .224 diameter bullets. I do occasionally pierce primers with low pressure loads, or if I seat the primers too deeply. Try using a mid-range load of a well behaved faster powder, like H4227.

Lil-Gun powder is noted for not producing high pressure. In fact it has been stated that you can fill a 22 hornet case full of Lil-Gun seat the bullet and shoot with no worry about excessive pressure. I use Lil-Gun in my 22 hornet and have never experienced and pressure problems with a 12.5 grain powder charge and 45 grain bullet. I would contact the Hodgdon powder company and listen to what they have to say about your problem with Lil-Gun powder. It looks as if you have an oversized firing pin hole in your old 22 Hornet a common problem in older rifles. I prefer Winchester brass over Remington brass in the 22 Hornet. Do you get any pressure signs with the starting load of Lil-Gun powder? Have you tried a different primer federal, Winchester, CCI.

Might be an idea to slug the barrel.
I had a Hornet built on a Martini Kadett action some 20 years back (Musgrave Barrel) and recently dug it out and 'scoped it for my 10 yr old boy.
With some old Sako ammo it shot reasonably tightly (around moa) at 100m. With Winchester it was not so pretty.
I bought some hornady .224 hornet bullets and reloaded, and had some pretty awful results. Bad groups, wide swings in velocity were the results of some fastidious testing.
On a hunch, I pulled a Sako and Winchester factory bullet. The Sako was .223 to the winchester .224, which was the same as the Hornady. I then slugged the barrel of the rifle, 3 times to be sure (I just would not believe the first 2 tests)and found it to be .219".
Trying to get Hornet bullets here is a joke, and the next batch coming in to one of the local wholesalers is end Jan 2003.
I am trying to get a couple of boxes of .223 and .222 dia bullets to test.
Gerhard (GS Custom)is also a delivery problem here and I am waiting for some bullets from him for this little rifle.
So back into the cupboard the rifle goes

It seems to me that the firing pin hole is of a size that won't support the primer. This is what has caused this "effect" in all the firearms in which I've seen it. Primers will flow under pressure but they look different than when the firing pin hole is oversize and allows primer to be easily forced through it and around the firing pin. You will note that the primers aren't severely flattened just cratering.

I use CCI primers for all my reloading and I don't feel that they are particularly sensitive to pressures or to put it another way, they aren't "soft" primers. Also, use of this quantity of Lil'Gun is not something that will cause excessive pressures with this bullet, unless...

Your bore is severely undersize, say .221 or less groove diameter. Still, it seems that with no pressure signs (I don't believe that this is a pressure sign and using primers as a pressure sign is notoriously unreliable) the firing pin hole is the most likely culprit.

You can try changing primers to find a brand with a "harder" cup but I think that in the long run, bushing the firing pin hole so that it has a proper fit with the firing pin.

Good luck and please follow up on this and let US know what you discovered so that we can either beat ourselves for our ignorance or learn from your experience.

Hobie,

I had exactly the same thoughts - more or less. The primers are not flattened, and that should happen before cratering, as a sign of pressure. I think factory ammunition is next, and if the primers look the same, then it's either bore size or firing pin fit. Lil-gun produces some remarkably low pressures, so that really should not be an issue.

I do have one other notion, however, and it's actually the opposite of what you have suggested (sorry!). Small pistol primers are quite commonly used in Hornet loads, and it may be instructive to try those. They are softer, so may flow more, but if the weak main spring hypothesis is true, rather than firing pin fit, then maybe the firing pin will embed itself further into the primer cup and the flow will be less as there is nowhere to flow to. As it happens, I have a few CCI 500s, so that could be worth a try - it won't cost a whole lot.

I will be sure to let you know the outcome of the exercise.

You can not put enough Lil Gun in a Hornet case to cause high pressure with a 40/50gr. bullet. Think bushing the firing pin is the first place to look.

Patrick,
I regularly use 13.2 to 13.2 grains of Lil'Gun, and have yet to see a pressure problem. I use Federal #100 small pistol primers. I also use Winchester brass, which generally weighs more than Remington brass (and should therefore be thicker, thus creating more pressure).
Regards, George.

Well, it's been a while, so it's time for an update.

When I checked the pistol primers I had, I decided not to use them because they were a) old, and b) given to me by someone who may not have stored them properly. So I have some Rem 6-1/2 on order, and will try those when they arrive. Looking at other posts relating to Hornet primers, it seems that these are more or less purpose-made for the Hornet by Rem.

Anyway, while waiting for these I have tried some factory ammo in the little rifle. They come out looking much the same. In the image below, the top row are my handloads, the bottom row are factory. (They actually look worse in the picture than they do in real life!)

I will post further results after I try the new primers.

Patrick

Very good photos. Looks like a problem with the firing pin/firing pin hole/firing pin spring. Or a combination of these. For a quick check can you shim the firing pin spring for greater tension without coil binding it? Check also that the edges of the firing pin hole are square edged.

Also your firing pin is not striking the primer dead center. That rifle will never be a good shooter with those off center firing pin strikes. Off center primer strikes produce inconsistant ignition and accuracy will suffer. Since your firing pin hits off center you may have more than one problem with that particular 22 Hornet rifle.

Reloader66,

I read your post earlier, and found it quite thought-provoking. I had a look at used cases from all my rifles, and then my son's case collection. Not exhaustive research, but enough examples to tell me that only two out of 40 or so different firearms' strikes were dead center. For the record, both were mine - a model 66 Mauser in .243 and a .357 Colt Python (sadly confiscated and destroyed a few years back due to legislation here).

The thing is, does it really matter that much? I have a Sako 75 in .222 Rem, which doesn't strike dead center, but it's what I think you'd refer to as a "keeper". Certainly sub half MOA if I do my part. So the thing I would question is whether being off-center is an issue, so long as it's consistent. If you hit the primer the same way every time, surely that's the main issue. Consider also that these are small rifle primers in a quite magnified picture, so any irregularity may appear worse than it actually is. Further, I didn't take the trouble to ensure that all cases were facing the same way, so some may appear more "off" than others.

This is not an issue I have seen discussed before, and I think it might open up some interesting debate to post a new topic discussing it. I wonder whether any research has been done in this area.

Anyway, thanks for taking the time to share your thoughts.

Update time, for those who wanted to know the outcome.

I tried the gun today using Rem 6-1/2 primers. I think the results speak for themselves. In the picture, the four on the left are what prompted me to start this thread. The four on the right I fired today, and they had the Rem 6-1/2.

Job done, I think. Thanks to all for your advice and suggestions.

Patrick

So a harder cup primer did fix the "problem".

Patrick,

I am now using L'ilGun and the 35 gr. VMAX (derided by some, I was given a quantity so will use). My best load has been 13 gr. L'ilGun with the CCI 300 (small rifle) primer. With H110 it does best with the small pistol magnum primers. Just interesting.

BTW, I don't know if I mentioned it but my Hornet is a TC Contender 21" factory barrel with a 4X scope. I need to go back to the range to chronograph it.

Patrick,

I have the same rifle model, and had the same problem. I solved it as you did: I changed primers. First I used CCI small rifle, and had these craterings and even had some primers pierced. However, with Federal small pistol everthing works just OK.

And it couldn�t have been a pressure problem for me, as I had the craterings when loading with the Norma 200, which is too slowly burning for the .22 Hornet. In fact, it doesn�t burn completely, but leaves unburned powder in the barrel. OF course I have changed to a faster poweder, the Norma P-123. Lil�gun isn�t availble here.

Best regards,

Fritz

Hobie,

The Rem 6-1/2 are softer, not harder!

I have tried the 35 gr Vmax too, like you I am using 13grs Lil' Gun, and the rifle seems to like the load. This afternoon, all being well, I will discover what the local fox population think of the Vmax......It's a beautiful still, clear, sunny spring day - I just HAVE to get out there.

All the best

Patrick

Fritz,

It's good to hear I'm not the only one!

I'm amazed you don't import Hodgdon powder in Sweden, and I thought we had a lack of choice here!

Patrick

As another data point, if you look in the A-Square loading manual you will find a section on this subject. The pictures could be duplicates.

One caution, which probably isn't a real problem with LilGun. The term "fixed the problem" was used a couple of times. That's not strictly true. What you do by using a harder primer is patch the problem. The underlying problem, whether too large a hole, bad firing pin tip or weak spring still exists. In a situation with another powder and load, the gun may suffer a primer failure sooner than a comparable rifle without the fault. Considering that it is a Hornet and this is likely the optimum powder, I wouldn't be worried enough to do anything to it. However, I would take it easy with any future experimentation.

I shoot a ZKW and four M-527s which is the modern equivelent.

The puckered primers are the result of a weak firing pin spring. Replace it and the problem is solved.