No. 4(T) Results with R-P Cases

Between the Herter's, PPU, and the No Name cases, the No Name brand is as close to what the original cases would have been with the Herter's coming in next and the PPU cases falling in last but having the best overall case conformity of the lot. All of my cases are fire formed to the rifle and my Go-To reloading tool is my Lee Loader Whack-A-Mole kit. The barrel on my Maltby is a 5 groove BSA Shirley made item that was still in its mummy wrap when I purchased it and as of this writing, currently has 550 rounds through it. The cases on the other hand have been used in other rifles in the past until recently and have since been solely dedicated to this one rifle. The three brands of cases have been reloaded at least 10 times now and are starting to show signs of stress. This is where the FEEL and HEAR comes into play. When I am target shooting I will shoot a group of ten shots at a target and move on to the next target after a 15 minute break. Every shot will typically FEEL and SOUND the same, (Recoil&Report).

A ruptured case will intensify both the recoil and report of that shot, throwing that shot high and to the left. I only shoot in small batches of 50 rounds per session and will typically leave that session with an average of 4 ruptured cases and 1 perfect ten shot grouping. For me, it is not exactly about what is the better brand of case but rather how long can I reload that case until it subsequently destroys itself and throws my ten shot accuracy  group off kilter...

Yes I can also feel a dud.

I call them sometimes before the bullet reaches the target at long range!

Other range users look at me like I'm crazy when I shout "ALIBI"

R-P used to be my Go To brand, but no more I'm afraid.

Now its HXP (if I can find them) Or PPU if anyone has any.

The only rifle I currently use RP cases in is my Dad’s No. 4(T).  I did some initial load development with RP cases in my Long Branch Fulton regulated rifle which did give good results, but soon changed to Canadian military cases. 

What stands out in the batch of RP cases I’ve been using in the (T) is the relatively thin necks.  Rims are also thin.  

I could not come up with an explanation for is why the 1951 Canadian Dominion Arsenal factory loads shoot so much better than my handloads with RP cases?  My handloads have shot some pretty small groups, some examples of one ragged hole for 7 shots or more, but then the dreaded flier throws the group out to 3 inch extreme spread at 100 yds.

The average of ten RP case necks measured 0.011 inches vs DAC ‘51 at 0.014 inches.  Add to that, the Mk 7 bullet loaded in the DAC ‘51 is .312 inches vs .311 SMK in the RP case.  Now we get a difference in neck diameter of .007 inches.  That’s a lot.  And that could result in the .311 SMK bullet sitting .0035 inches lower in the chamber than the DAC 51 loads. 

Here is the other odd thing.  Using my Hornady case headspace length gage, ten fired DAC cases all measured the exact same length to the shoulder datum, 1.8515 inches.  The RP cases are all over the place, they varied by 0.007 inches.  So, some were likely headspacimg on the rim, and some on the shoulder. 

My plan is to load new PPU brass with the Hornady .312 Match bullet.  This won’t quite give the same neck diameter as the DAC cartridges, but much closer (0.002 inches smaller vs 0.007 inches smaller with the RP case and .311 bullet).

Going to be a while until I can test out this theory. 

The last batch of RP that I bought were not the usual standard. I had some cases already split form manufacture in the batch. Seems irregular thickness and or metal quality. I only use PPU now, but still have the RP cases as a secondary stock now.

I bought these R-P cases more than 20 years ago.  I still have another unopened bag of 100 cases.  

One other discovery in the investigation is that annealing the necks and resizing in a full length die has pulled the neck out of concentricity with the case body.  I don’t have a concentricity gage, but you can see the bullet wobble as you roll a cartridge on the table.  That’s another thing not conducive to accuracy.  Cases neck sized in my Lee Collet die don’t do this. 

  

I went back thru my reloading notes and suspect I bought these R-P cases around 2005 (I though it was earlier than that, but I used Canadian Mk 7 cases prior to that). May have even been later. 

I think these are headed for the recycle bin.