My new Cooper in 22 K Hornet should ship on monday. I have 35 and 40 gr Hornady's and some lil gun. Anybody have a pet load that does well in a Cooper k hornet. I been shooting 13.5 in my anshutz in k hornet with either bullet.

JD

i use 14.5 lilgun & 40 gr

I've had better luck with AA1680 in my K-Hornet than any other powder. The 35 gr. Hornady V-max does well (and is super-explosive). It also sheds velocity like a ping-pong ball. Since your Cooper is a single shot (correct?) and the overall length of the cartridge is largely irrelevant, I'd recommend the 40 grain plastic-tipped bullets. Sierra Blitzking, Nosler B.Tip, or Hornady V-max all have similar very good potential -- try them all and use the one your Cooper likes best. If you like conventional lead-tipped bullets, I've had best luck with the Sierra 45 gr. Varminter.

As to powder charges, each gun is a rule unto itself. However, it is difficult to get too much of either AA1680 or Lilgun into the case in most instances. Lilgun will provide higher, but more erratic velocities. Standard velocity deviations will be much closer with AA1680. Despite its shot-to-shot velocity swings, some people report acceptable accuracy with Lilgun and use it in order to reach the highest possible average velocity. In my estimation, if you are concerned with wringing the most velocity out of your gun, you would have bought a .223 or a .220 Swift. Hornets, even the K-version, are intended for modest velocities. Be happy with any reasonable velocity at which you can achieve the best accuracy.

I decided to jump in here cause my Cooper K-Hornet in Montana Varminter was a complete anomaly and showed me that the old adage each rifle has it's own personality is completely true and one should never take a "preconceived idea as fact and load on it" .
First my K had a headspace problem, I fire-formed with 13.3 grains of Lil'Gun in a WW case with a WSR primer under a 40 grain V-Max. After fire-forming a fired case wouldn't fit into the shellholder due to the primer protruding a bit from the primer pocket, a "headspace problem". Cooper was great and after sending it back the rifle returned and while some better still protruded primers a bit. After a second trip back Rob told me that they had cut the tightest chamber in a .22 K-Hornet they had ever done. The problem with headspace was solved, then the real mysteries began!
Short version was that I would fire-form with the above mentioned load which is a standard Hornet load, the cases formed perfectly at a repeatedly chrono'd 3,000ish FPS and it shot literal bug holes. Here comes the curious part . After being formed if I put the "exact same" load back into the formed case it chrono'd 3,450ish FPS and blew the primer plum loose (they'd fall out in your hand)????? I called Rob at Cooper who is a true gentleman and a pleasure to deal with (unfortunately for Cooper arms he has since left), he stated that Lil'Gun was the culprit and was a pistol powder not for rifles (it's a weird powder I'll grant ya but great in Hornets and K-Hornets IMO). I also called everyone else on the planet that would listen cause as everyone knows you fire-form a parent case with one load and then add more powder and gain velocity right? Wrong! not in this one.
I ended up talking to Dick Saunders who is a small caliber legend and I know he was convinced I'd took to day drinking, cause everyone knows that just isn't how improved cases work! Well I hadn't.
To cut to the chase Dick suggested I call a fella named Todd Kindler who was then the editor of a magazine called "Small Caliber News", Dick stated this guy knew everything about small cased rounds. I took his advise and called Todd, Todd stated it made perfect sense to him. He said that after forming especially with that tight chamber the case became much more efficient and that I needed to back off below the form load and try that. He also talked to me about small calibers for a couple of most enjoyable if expensive hours and I hung up and ordered a new Cooper Varminter in .17 MachIV about 15 minutes later but that's another story altogether.
I took Todd's advise as well about my K and where that rifle ultimately ended up was that it fire-formed cases with 13.3 grains of Lil'Gun in a WW case with a WSR primer and 40 grain V-Max at 3,000ish FPS and after forming I "backed up" that load using all the same components to "12.3" grains of Lil'Gun and all else the same for 3,250ish+ and again bug holes. A full grain less powder for 250ish FPS gain??? Go figure. The velocity though was what I considered "way fast" (unnecessarily so), but it wasn't the point, it just came together at the accuracy sweet spot. Rob at Cooper was one of the many that thought I was nuts (probably am but not in this instance) so I took this picture of forming load and formed load group,5 shots at 100 yards of course and sent them to him.



Since this time which was right after Lil'Gun came out I believe maybe, 2000ish? I know Hornady was just intruding the 5th Edition Loading Manual showing 13.7 grains of Lil'Gun as max with a 40 grainer in the standard Hornet (they have since reduced that max load).
I couldn't agree with Stonecreek more when he says each rifle is a rule unto itself! Truer words were never spoken!!! Since this experience I have loaded for many sub .22 caliber wildcats with improved cases (that's my thing ). That said I make it completely clear that everyone of them has been approached as two different loads to develop for each rifle, the fire-form load and then start low and work up slow developing a formed case load. It's never happened to me again but the once was enough to make a believer outta me for keeps. A good example of that would be that with the K I had and my lots of Lil'Gun and WSR's butchloc's obviously safe in his rifle load of 14.5 grains Lil'Gun and 40's which I'd guess is fairly standard K-Hornet fare???, would have been catastrophic in my rifle if 13.2 grains blew primers at 3,450.

I know some here will also think I've took to day drinking but it ain't so, that's a many times repeated test complete with much head scratching, case ruining, wailing and gnashing of teeth before the answer was found.

Two other points at the risk of sounding like the social avenger (which I ain't), one when Coopers pop primers they come right back through the bolt into your eyes they vent gas terribly and I'm a guy that's popped a few primers .
Second and even more preachy (sorry), if Stonecreeks right and each rifles a rule unto itself (he is IMO) asking for pet loads is asking for trouble, these ain't cookie recipes. I'm sure I don't need to say that as any cautious reloader would take someones personal load and back off by 10% to start working up but it's the Hunter Safety Instructor in me so I had to say it, sorry.

All worry warting aside congrats on the rifle, great shooters and a real fun round!!

One last aside. Since my madness figuring the anomaly Cooper I ran into one other fellow that had had the same experiences with his that I had, it was either here or on another site I hangout at but I gotta tell ya it was sure nice to find someone who understood first hand. That means if it's happened twice it could happen again.
Happy ending to this story by the way, after the problem was diagnosed that K was a shooting son of a gun and terminated many rodents!! It was also a great lesson for an ole fart that had been reloading since the 60's and pretty much thought he had it all down by the numbers, "WRONG"! A guy gotta think outside the box once and a while .

My cooper is blowing pistol primmer back on fire forming, Once formed no problems,I am at 14 grs and 40 gr vx no problems,

JD

I don't know what powder your using so not sure of the pressure.
I would like to mention a two p-art article written by Ross Sefried on the .22 Hornet a number of years back. Half of the article was in Handloader one month and the other half in Rifle the next. Excellent article in his typical thorough style.
He spoke at length on the use of pistol primers in the standard Hornet loads. Said it was effective with many powders with the exception of in the little gun loads. No Joy for ole Ross with Lil'Gun and pistol primers.
Maybe I haven't been listening but with all the Hornet and K-Hornet stuff I shoot I don't believe I've heard much talk on pistol primers with the K, I know I'd had great success with several K-Hornets and I've never even considered going from small rifle to small pistol.

On the off chance what you saying is that your forming Hornet to K Hornet using 14grain of Lil'Gun I wouldn't be at all surprise to see that combo blow primers.

Pressure aside if your primers are backing out during forming without knocking the pockets loose it's a headspace issue.

I am useing pistol primmers because that was all I could find. I am loading lil gun. 13.5 is the fireforming load. That about full, maybe a 1/4 inch of neck showing. The primmers push back with out showing pressure sighs. Its not headspaceing on the rim. I use a flat punch to push them in a shell holder. Once the cases are formed no problems.

JD

I have had less consistency with SP primers than SR primers in all of my Hornets and K-Hornets.

I've also found that velocities with Lil Gun vary wildly, so I don't use it. Ironically, Lil Gun is extremely consistent in large bore, heavy bullet handgun loads for me, so I use my supply for that purpose.

Most pistols using small pistol primers probably have a SAMMI max of 25 to 35 K-PSI. The Hornet is listed as a SAMMI MAX of 43,000PSI and that's running book velocities of 2,400 to 2,600ish with 40 grain bullets. I take a W.A.G. that at 3,000ish FPS we are probably topping that fairly substantially.
Add an improved chamber and run the velocity up to 3,250ish FPS (these are all just arbitrary numbers), and whatever kind of PSI it's running it's darn sure more PSI than the small pistol primers are intended to handle.
Personally if all I had were small pistol primers I sure wouldn't be running max loads intended for small rifle primers but that's just me. If all I had were small pistol primers I'd back up the load till the primers quit acting up.
To me if the primers are coming back out of the case on firing it's either pressure or headspace, neither one is something I'd consider just continuing with.
The only other possibility that makes sense to me is completely opposite in that possibly those pistol primers aren't hot enough to get that Lil'Gun lit and the primers are backing out before the case is formed . If it isn't headspace or pressure something like that has to be the culprit. I still wouldn't personally run full power K-Hornet loads in a case using small pistol primers.
I agree with Stonecreek, in that I've never had any luck with small pistol primers in the Hornet although I know some have.
Where my practices differ from his is that to me while Lil'Gun does indeed show large velocity spreads, at the effective distance of the Hornet (250ish?), it really doesn't matter that much. According to my ballistics program a 40 grain V-Max with a BC of .200 at 3,000FPS velocity sighted in at 200 yards is +1.81 at 100 yards and -3.37 at 250 yards. Even with a huge spread of 100FPS at 3,100FPS sighted the same it is +1.63 at 100 yards and -3.12 at 250 yards. Not much. Plus it usually isn't that big of spread, the accuracy is great and the big banana is it meters fantastically on my Redding Competition BR30. All that adds up to an acceptable weirdness out of an admittedly weird powder in the Hornets and K-Hornets for me. That said
I sure understand guys that don't agree with my opinion on this one.
Keep us posted on this one. Real curious?

Montdoug

I have never seen any data to suggest what the working limits of pistol primers are. I am using Federal small pistol mag primers.

Lil gun is marketed as a shotgun and "mag pistol powder" that does well in the Hornet.

I don't think that they would be getting good performance in pistols if rifle primers were required to get it lit. According to the Hodgen site - The K- hornet with a 13.5 gr load of lil gun ,and a 40 gr bullet is reported to give less than 38000 cup at 3000 fps. The cup reading change about 5000 cup ,some loads with a heavier bullet will make less pressure than the same charge with a lighter bullet. The powder like most must have sweet range of pressure that it shines at. It produces faster loads in the hornet than the other powders listed.
I have not broke out the chrony, so I can't comment on SD, Groups have been bordering on 1/2 moa with 40 gr hornadays.
I have not had a very good range session I test 10 shot groups,with a warm barrel.

I have not found a bullet that will jam the rifling to form cases, primers are backing out due to low initial pressure or improper headspaceing on the rim. Once the case is formed it won't ever head space on the rim again, If I don't get case head separation I won"t worry about it.

I am working on finding a good starting load, to form cases with. Your 13.2 gr blitz king load may be it, the one hole test target Shot at 50 yards was a blitz king and a 13 gr of lilgun in a hornet case.

The cooper 38 has 3 locking lugs, and seems plenty strong, I have read you can't over charge the hornet with lil-gun , I have tested just a couple 53 gr loads with 13.5 lil gun In formed with mo more pressure signs, than the 40 gr load. I may not be giving the round enough respect, my other flanged rifle I load for is a 470 nitro, the hornet seems to cute to be much of a problem

JD possibly make your forming load using a heavier bullet set out far enough to jam into the lands like a 55 V-Max or something real long?
Another question? Are your primer pockets tight on re-priming after the on the cases that have the primers backed out?
What your describing sounds like my initial go round in my K. There was enough headspace that on forming the primer backed out far enough that I couldn't get them in a shell holder, in mine that was a headspace issue.
Good luck and keep us posted hey?

P.S.
As you can see once I got mine figured out it was a dandy! Bet yours is too!!!

quote:

I don't think that they would be getting good performance in pistols if rifle primers were required to get it lit.

Not so sure about that. They state Mag pistols and in them I use mag pistol primers not standard small pistol don't you?
Another discovery I made when Lil'Gun first came out was that I left it in a plastic tube container on a Redding powder measure over night, the next day when I removed it it was all "orange peel" textured in the Redding plastic tube. I called the Hodgdon tech's and was told that Lil'Gun has an extremely high nitro content and that was the culprit. Notice if you take a big pinch of Lil'Gun and squeeze it it compresses and kinda clumps, almost like it's a bit damp or something. I'm guessing that it's a real difficult powder to get lit uniformly and that's where some of the velocity swings are, especially in compressed loads??? All just guesses and supposition on my part but it sure does some strange stuff. I like it anyway as I mentioned but it is a puzzling propellant .