Trail Boss in BAM Rifles

[Grouchy Spike]

I'm a TB junkie, and I found a sheet from IMR with TB loads for the common rifle cartridges including 308 and 30-06.  It lists a min of 10 gr TB, 1176 fps and 13.3 gr TB, 1061 fps respectively under a 150 gr under a NOS BT bullet.

 

So I packed some 14.5 g TB under a 140 g 0.309 cast bullet for a 30-06 load in the 03A3 and gave it a try.  The recoil was minimal, but the group at 25 m was about 2 inches.  This load needs some more work.  I'll try some 168 gr bullets of 0.309 and 0.310 diameter, various loads of TB, likely some 140 gr 0.310 bullets too.

 

The capacity of the 7.5x55 case is about 98% of the 30-06 so I packed 12 g TB under a 140 g 0.310 cast bullet for the K31 and the holes in the target paper at 25 m were overlapping. That's encouraging.  I later found some 170 gr spire point cast bullets, so when the weather warms I'll try them with various loads of TB.  And I'll report the results.

[Grouchy Spike]

I began reloading 7.5x55 with a set of Lee dies, and had four cases that wouldn't fully chamber.  Investigation revealed that I hadn't removed all of the 'spring' in a Redding T7 turret press.  I  screwed down the FL sizing die a bit more and mostly eliminated that problem but I did learn to check all resized and trimmed cases IN THE CHAMBER, and then again after reloading.  A cartridge gauge would be a handy tool to have here.

 

The next challenge occurred when trying to seat the bullet just off the lands. The 170 gr GC Sil bullet from Norm Purcella has a OAL of 0.998" and a bearing surface which is about 0.357" long.  New PPU cases are mostly 2.180" OAL with some at 2.183".

 

I trimmed the cases to 2.166" max OAL so that the finished cartridge would have a length no greater than 2.795".  At 2.800" the bullet would be slightly marked by the lands.  The case length of 2.166" allows just half a red hair of bullet bearing surface above the case mouth. 

 

I don't know whether this bullet is a true secant ogive shape  as best would fit the K31 chamber.  It looks more like a tangent ogive, but I'm not so smart about that.

 

Reading that the Redding dies for 7.5 x 55 are sized for the K31 chamber, I now have two Redding sizer dies - a FL and a NeckSizer.  About half of my match loads were done using the Redding FL die, along with a Lee Expander, Seater, and Factory Crimp die.  The first half were done with the Lee FL sizer.

 

In the final QC chamber check by my dedicated associate, three cartridges apparently escaped the check as they chambered with difficulty during a match.  In  the chamber check, the bolt should close easily, without tapping it.

 

I visited the range with loads of 13, 14, and 15 gr Trail Boss and 30 gr of 4064.  Up to 100 meters the 15 gr TB grouped well at about 1525 fps as did 14 gr TB at about 1485 fps.  At 200 meters, the TB didn't do so well and the 30 gr 4064 was superior.  More work is needed with a chrono as these were one or two shot measurements, and also with 4064 loads.

 

There is no muzzle jump with loads of 15 gr TB and a 170 gr bullet.

 

[DUSTY BODDAMS]

GS, first off thank you for doing all the expirimentation to get the k31 truly up and running. Secondly thank you for sharing this with everyone! I know there were a lot of hours spent  trying to figure this one out. For the record I think the k31 has to be one of the best quality mil spec bolt guns out there and I think it's cartridge is world class.  Reloading this cartridge after you figuring it out won't be much harder than loading any other BAMM class rifle.  Dusty Boddams

[Garrison Joe]

Sounds about like the normal path that one wants to follow while working up cast boolit loads. 

 

I too like a neck sizer die, especially if I have just one rifle to load for that cartridge.  And a Lyman M die to get minimal belling for case to allow easy seating.

 

I find more accuracy faster when I have a selection of cast boolits to choose from.  There is rarely exactly one and only one bullet that shoots well in a particular cartridge, but each gun may have it's own pet.    Just was out Sunday shooting my 6.5 Swede.  Best so far has been some Reloader 7 and a 150 grain bore riding Lyman bullet.  Both 5-shot groups fired with the best load printed 1 1/4 inch at 90 yards.  Good for only being the third loading session for that cartridge, but I've got 3 designs I can choose from and a raft of powders.  Velocity seems, like most 6.5 Swedes, to want to be about 1500-1600 FPS.

 

Good luck, GJ

[Grouchy Spike]

Garrison Joe, I have M dies but haven't used them.  I've been using the Lee case mouth expanding die.  Am I overlooking some benefit here?

[Boggus Deal]

Grouchy, yes you are! If the Lee die you are using is that cone shaped one I have seen then once you use an M die, you'll throw the Lee ones away! The M die has a fairly long part that guides the neck and keeps it concentric, while a very slight step at the top expands the case just enough to allow the bullet to start squarely and not shave any lead. 

[Garrison Joe]

Yep, BD got it right on the head.  If you ever have shaved lead while seating, you have pretty well destroyed a rifle bullet.  It will still fire, but it won't hit what you want. 

 

Plus, the slight step is easier to crimp completely back down than the taper that most expanders put in the mouth. 

 

Good luck, GJ

[Grouchy Spike]

Boggus Deal and Garrison Joe, I'm a total convert to 'M' Dies! Thanks for the advice and recommendations.

 

One of the Texas cowboys recommended 170 gr rnfp w/gc for 30-06 using 18.5 gr 2400..1725fps....very good group at 100 yds.

 

I found another article by C.E. Harris with recipes for 2400 Powder, including a "Universal Load" for many .30 caliber military cartridges:  16 gr 2400 with bullet weights common for the caliber.  Read more here before starting this:

 

http://castboolits.gunloads.com/showthread.php?13425-Cast-Bullet-Loads-for-Military-Rifles-Article

 

YMMV

[Garand]

I've had good luck in shooting reduced load (1,400 fps) cast bullets in military bolt actions with Unique & Red Dot. Don't forget them.

[Grouchy Spike]

Garand, you are so right, and I saw a 'universal' recipe for Red Dot too.  I didn't have any Unique or Red Dot, only Trail Boss, 4064, and 2400 for rifle.  15.0 gr  Trail Boss and a 168 gr GC  for 7.5x55 K31 offered softer recoil, less 'crack' than 4064, so I tend to use the TB.  The K31 spits like an angry cat with this load.

 

But recoil and noise with  32.5 gr 4064 and a 168 gr GC in 30-06 was not objectionable. With the 03A3 the groups tightened up to minimum with this load.  I will likely try the 2400 in a 7.62x54R MN directly.

[Grouchy Spike]

7.5 x 55 Swiss K-31:  I've arrived!  After climbing the learning curve, aka 'load development', I can now hit the metal 16" circle target at 200 yds consistently with the K31 using 15.0 gr Trail Boss in 7.5x55 cartridge with a 0.310" 168 gr GC by Norm Purcella.  That's almost a full case of TB for 1500 fps, so no more velocity is available with this powder and bullet weight.

 

The Redding FL sizer and (thanks to advice by Garrison Joe and Boggus Deal) the Lyman M die, coupled with stringent quality control on bullets, TTL, seating depth and COL, delivers some consistent performance.

 

And did I mention that I chamber check EVERY round after reloading?

 

From you purveyors of the fine Swiss K31 carbine, what are your loads?

 

And next is the Mosin Nagant.  Does anybody have any recipes to share?  Any experience with accuracy?

[DUSTY BODDAMS]

GS, sounds like you are up and running with the Swiss. The mosins with just a few tweaks can be scary accurate. Probably one of the most underrated surplus guns out there. I would have to look at my notes but I think my best load was 4759 with 18 gr.  I think  a 190 GC from norm sized at .313 this put me in the 1 1/2" at 100 yards. Really with good bores I haven't had any mil spec bolt guns that didn't shoot really well. Speaking of BAMM get ready for an exciting multi stage match at the Texas state WB competition. Bring at least 40 rounds and we will try to put most to use! Dusty Boddams