Hit the range with the new to me Rim Rock heavies. I did not realize when I ordered from Selway that these were the 15BNH vs. Hard Cast. Having some experience with 800X and X-Treme 220's I started with 8.0gr up to 8.3gr charges. Win primer 1.250 OAL in once fired Win brass. Nail test on bullet confirmed they were pretty hard unable to be marked. All charges weighed on beam scale. I tried 1.255 OAL but they would not plop test in either barrel. They are sized .401.
8.0 800X in LWD 6" produced 1194 fps with enough smile that I only shot ONE
8.0 800X in KKM 4.7" gave 1135 fps no smile
8.2 800X in KKM 4.7" 1133, 1142, 1151 fps no smile and the 3 went into ¾" at 25 yards
I had loaded up 10 at 8.3 since past data showed UW using 8.4 with the 220gr Rim Rock. First one went 1165 through the KKM 4.7 with a smile so I quit further testing planning to pull the remainder. With only one round down the 6" and five in the 4.7 I had lead swipes half way down the barrels! Its hopeful that their Hard Cast will allow better results but I have 1000 of these to shoot up. Plan to reduce load to the point of no leading for a practice load or maybe try the Longshot but do not expect different results. If anyone is interested in testing some, I will pass them on at .09 each plus actual shipping.
Jazzsax8, Thanks for your report. What recoil system were you running in you Glock? (captive vs. non captive and spring weights if known)
I see you mention that they are 0.401" but have you measured the diameters of those RimRock's? If they are less than 0.4010" that maybe the reason for the leading. Also if you pull those you talked about, measure them as well to see if your loading operations squeezed those smaller that the original non loaded bullets as a comparison.
The reason I mention this is, that I size my 10mm/40 cal cast bullets at 0.4015" and they work well with most barrels with little to no leading. However test of the Underwood and Double Tap did show some leading in my testing... :-[
I have noticed that using the LEE FCD as a final finish die on loaded cast bullets can squeeze them down a bit...that can cause undersize bullets which can lead the bores due to blow by of the gases.
On a final note, the Wide Flat Nose style may need to be loaded shorter for them to feed reliably and fully chamber. DT drop the COL down to 1.2420" to facilitate more reliability.
Good luck getting it all worked out. ;)
I am using the Wolf dual spring non captive at 23#'s that still throws hot round empty's at least 20' and have tested its weight and its right on the money.
I measured bullets from the box and they are a solid .401 and as you turn them and some seem a little out of round going .4015. They do have a solid base with no taper.
Pulled three loads and the bullets measure .4008 so it did squeeze them down just a hair using the Lee FCD. Outer measure of case mouth before pulling was .422. Since the case mouth thickness measures around .11 to .115 simple math indicates a little squeeze on the bullet. Before using the Lee FCD they would not chamber at around .424-.425. I did seat them first with the Hornady die to length without crimp then used the FCD that puts a little too much on them. I was in a hurry this time and ideally I plan to use the guts of the 10mm FCD in my .44 cal FCD to just touch the mouth back in place enough to pass the plop test.
I will try the shorter 1.242 and crimp them better as described above that might give better results. I should probably start around 7.6 grains though to maximize safety!
It is interesting to me how times change. A 15 bhn is hard cast by cast bullet standards of most people who cast their own. It certainly qualified for Elmer Keith's 44magnum loads cast from 16:1.
I would say try softer and work out the issue with the bullet being squeezed down. A harder bullet will have less obturation to bump back up and therefore more plasma cutting as gas escapes around the bullet. Add in the lower melting point of an alloy like Linotype and I bet your leading gets worse not better.
This can be a real problem with heavier than 210 grain in 10mm. The bullets have to be seated so deep that you can't help but squeeze the base. This is one application where I think a gas check design makes a lot of sense.
I've been shooting 11 bhn 175 grain hollowpoints at 1400 fps.
Hardness isn't the issue. Wjat diameter are you barrels? For a bullet that hard, you need 0.001" over. If those KKMs are like 0.399", those bullets may actually be too big. Usually not an issue, but sometimes going with a smaller bullet helps in 9mm.
I'm thinking it's both the lube not working and bullets too big. *shrug shoulders*
I just slugged the KKM barrel and it's a solid .400.
My vote then is the lube isn't worth a damn.
Hard lube can sometimes be an issue as well.
Like you I run 11-14 bhn bullets pretty hot without issue. My bet is the very base is being sized down from deep seating.
Back to the range with Longshot and the 220 Rim Rock. This time I took the guts out of the Lee FCD and put them into my Lee FCD .44 to crimp the case mouth just enough to get the drop into the barrel. Case mouth ended up at .424-.425. I pulled a couple of bullets and it was still swaging the bullet down to .4005 from .401. I shortened the OAL to 1.244. Crony was 15' away, temp. 62deg. Glock 29 w/Wolf 23# uncaptured dual spring.
6" LWD barrel
7.0 gr 1090 & 1068 fps with some leading so I switched to the KKM barrel
4.7" KKM barrel
7.5 gr 1085, 1069 & 1091 w/slight smile and was also leading up after only 3 rounds
Had some 7.6 & 7.8 gr loads along but due to the smile above decided to just pull the bullets. Not sure how to make these work at this point. I assume the historical pull down Underwood Rim Rocks are the harder cast bullets using up to 8.4gr of Longshot with way faster velocity. The ones I am using are 15 BNH marked Cowboy that should fill at the base when pushed hard but are not getting the job done even using aftermarket barrels. They have the blue lube in the groove that is missing on some probably due to shipping that I carefully inspected before loading. Is there anything I could do in my loading procedures different to make these work? If not I will back them down to 750 fps + to eliminate leading.
Try tumble lubing them with LLA. Its like $5 for a tube