Ruger No
Actually, what you're seeing, I've to a greater or lesser degree have seen in all my Hornets, and the .30/30 as well.
This is attributable to the slight shoulder angle, normal tolerances, and relatively low pressures of the two cartridges.
TheCZ:
What is happening is that you have what appears to be cases full length sized that have been excessively sized.
I don't think that your headspace is all that excessive, I had simular results with an H&R Topper back in the early '70's while I was in college.
It appears less with the rifle primers because they are indeed developing slightly more pressure than the pistol primers. (I have used both with the same 40gr Sierra HP and 12.5gr of Lil-gun is my preferred powder charge. Best accuracy -just under 1", and 3,000fps). This load is about 10,000 to 12,000 psi under most other loads for the Hornet.
At this low pressure, there is not enough back thrust to stretch the case to force it back against the bolt face and "re-seat" the primer back into the primer pocket.
The solution I've always used is to fireform the brass with the first loading by seating the bullets out to minimize the setback and stretching. And then, I partially full length size to just "kiss" the shoulder. I also usually trim the cases after the first firing to get the case length right after the first stretching.
Yes, I find that full length sizing this way gives better accuracy in most Hornets because, they then "lie" in the chamber the same way each time. My best accuracy ever with a Hornet came just this way with 11.4gr of AA-1680, a Winchester Small Pistol primer, and a Hornady 50gr SX seated out to 1.860", to where they just touched the rifling in my Ruger 77/22kbz for a .560" 5 shot group. Cases had been weighed and segregated, and as stated, once fired. I have never been able to duplicate this since! Even with same batch of brass!
Just perfect range conditions, I suppose! But I did have several witnesses, and I still have the group!
FWIW, I recently was tinkering with some .30/30 loads and RL-15. At 1.0gr below max, I was getting the same primer extrusion you are getting with your Hornet. Upping to max., the extrusion went away, but after resizing and mikeing them, I got .005" case stretch too!
Check your OAl's after re-sizing the Hornet cases. I think you'll find that the primers that were extruded less, had actually been pushed back into the pocket due to brass stretch. Yes, it comes from in front of the web and will in 7-10 loadings cause incipient case separation.
Again, as stated, the solution is to not completely size to where the shoulder is set back. However, I have tried leaving the slight "hump" in front of the shoulder with the "secondary" shoulder left where the neck was not completely sized down. I don't get as good of accuracy this way due to the slight but unavoidable inconsistenacy in the roundness of the chamber causing the bullets to be slightly misaligned with the bore. Sizing just to the shoulder is best in my experience with both the .30/30 and Hornet.
Best solution besides "tweaking" the reloading?
Rechamber to .22 K-Hornet. However, this MUST be done by a VERY GOOD gunsmith, and setting back the barrel to completley clean up the chamber and re-cut the throat. Back in the early '70's, I picked up a used Ruger No.3 in .22 Hornet. It had been reamed to K-Hornet, but not marked. Imagine my suprise at extracting the first case I fired! I found out quickly too, why the gun had been traded! Groups the size of Basketballs were the norm! But, I at least let the RCBS dies that cost me a fortune go with the rifle! The run-out and off-centered chamber was very evident with the fired cases. Cases would only last 2-3 firings before they would split just in front of the web from excessive working.
I'm just content with my Hornet and 1.25" groups, as it serves me very well and is an enjoyable rifle to shoot, not to mention inexpensive too! I suggest you leave "well enough" alone, and just figure out what your Hornet wants to be fed (as you have already found out), and enjoy it! After all, its not a bench-rest gun. If you want REAL tack driving, get you a Sako 75 Varmint in .22 PPC.
Now those will shoot .75" on a REALLY BAD day!
Actually, the best of all possibilites would be to send some fired cases to one of the die manufacturers and have a custom set of dies made where you will have minimal sizing both in diameter and length. This sould do a better job of "fitting" the cases to your chamber. I actuality, this may be cheaper than having a gunsmith "blue-print" the chamber and action.
There is a fellow in Conneticut that specializes in doing this to Rugers as they are especially apt to have excessive headspace due to the way the bolts are two piece. I "fixed" mine by making a "c" ring to go inside the bold from a piece of aircraft safety wire. Before doing this, it would not extract fired cases because of the excess "slop" in the bolt prevented the lugs from "camming" the case from the chamber upon opening. He too charges 135.00 to 175.00 for this, which includes setting back the barrel and recutting the chamber to either a minimal Hornet, or a K-Hornet chamber.
I have passed on doing this "solution" as I would probably trade the gun before putting that kind of money into it.
Mostly because as is, as stated, it will shoot 1.0" to 1.25" with the Sierras, and has taken over 2 dozen deer, a red fox, and numerous crows, and other pest species. Good enough for Me!
If I need better/more, I get out the Rem Mod7 in .223!