This time you get two articles in one. Loads for 7.5x55mm Schmidt-Rubin by Lloyd de Vore of Wilbur, OR and Neck Sizing the 7.5x55mm Schmidt-Rubin by Larry Murray of Shelton, WA appeared in Fouling Shot #154 / Nov-Dec 2001.
Loads for 7.5x55mm Schmidt-Rubin
A question was recently asked on the cb-list, as to “What is a Good Load for the 7.5 Swiss (7.5x55 Schmidt-Rubin)?”, specifically, the K-31.To check that out for myself, I have cast up a number of different .30 bullets for trial in my K-31. My particular gun is in almost new condition, metal-wise, but only in about NRA-VG condition as far as the wood. It is, however a relatively good shooter with jacketed bullets, considering the issue iron sights and my aging eyes.
Here is the result of the first cast bullet and powder charge tried in my rifle, shot today, at the Roseburg Rod & Gun Club range:
Bullet - Ideal 308329, lino, 174.9 grains, sized 0.310” in Saeco lubrisizer.
Powder – Varget, 32.5 grains. I chose this charge by using Virg Edwards record-setting load of 30.6 grs. of Varget in his .308 with a slightly heavier bullet, and increasing it to allow for the .30-06 powder capacity of the 7.5x55. Note: I am not recommending this or any other load. I am just reporting what happened with it in my rifle.
Primer - F-210. What I had lots of on hand.
Case - Winchester .284 case opened to take .30 bullets, simply by running the cases into an RCBS 7.5 Swiss sizing die with a tapered expander ball.
Anyone can, with a bit of effort & patience, taper an expander ball with a file, a grinder, course emery cloth, or an India stone.
Be sure to check your brass for overall length. I just run mine into an RCBS file-trim die, and use the file if necessary.
Lube(s) - I tried two, 40 rounds with Thompson’s Blue Angel and 20 rounds with Lyman’s Super-Moly.
Seating - This bullet chambered very nicely, with the bullet seated so that 0.010” of the 0.083” high Hornady gas check, lot 394, protrudes below the case neck. This leaves 0.073” of the gas check up in the case neck, so “Noooooo...Problem” with the bullet being exposed to raw, hot powder gas upon ignition.
Seated at this depth, the cartridge also feeds nicely through my magazine, and can be ejected without firing, and without damaging the bullet or pulling it from the case. (It doesn’t “stick” in the bore if you eject it unfired.)
Results
It took me approximately 10 rounds at 100 yards to get the sights set appropriately for shooting at a nice big 100-yard M.L.R.A. Rifle Target. The sights are the issue K-31 open “U” tangent rear sight, and adjustable (by drifting) blade front. This cast load shoots approximately 4” high at 100 yards with the sights set on the 100-yard notch. Nothing lower is available on this sight, but, by using a six-o’clock hold on the black, the groups are exactly 1” above dead center in the bull.
In my rifle, this load also shoots approximately 8” right from my jacketed load of 150-gr. bullets and 46 grains of IMR 4320. The front sight is drift-adjustable on a diagonal, however, and with it drifted until the front of the blade is just even with the front of the sight base, it is dead-on for windage.
As for groups, with two people alternating shooting the rifle in no particular sequence, the Thompson’s Blue Angel rounds were putting 5 shots into groups which averaged well under two inches. The best group was 1-3/16”.
Unlike what I expected, the Lyman Super-Moly did slightly better, with a smallest 5-shot group of 1-1/8” and an average of about 1-5/16”.
As I said, I have old eyes. Much of the time I could really not see the rear sight. I did use a rear sandbag and one of the cheapo Midway plastic front rests. The trigger on my rifle is a very nice, original military two-stage, with the second stage estimated at 2.5-3.0 lbs.
Many thanks to the Lister who brought up this subject. This load shoots so well I am not sure I want to test any of the other bullets I cast for the purpose. I am also going to reserve this rifle exclusively for “lead-only” from now on.
And, now, I plan to buy a B-Square mount so I can put a “scout-style” scope where the rear sight now sits. That way I can always put the original military rear sight back on if I want/need to. With a decent scope, and this load, this gun should be fully competitive in Production Class if it continues to shoot this way. I figure the ability to see what I’m aiming at should take at least another 1/2” or more off the groups.
By the way, this is one of the most pointy, long-nosed cast bullets I have ever seen. Without the boat-tail, it is slightly longer-nose, and slightly more pointy that the military ball 174 gr. M-1.
Loads for 7.5x55mm Schmidt-Rubin
A question was recently asked on the cb-list, as to “What is a Good Load for the 7.5 Swiss (7.5x55 Schmidt-Rubin)?”, specifically, the K-31.To check that out for myself, I have cast up a number of different .30 bullets for trial in my K-31. My particular gun is in almost new condition, metal-wise, but only in about NRA-VG condition as far as the wood. It is, however a relatively good shooter with jacketed bullets, considering the issue iron sights and my aging eyes.
Here is the result of the first cast bullet and powder charge tried in my rifle, shot today, at the Roseburg Rod & Gun Club range:
Bullet - Ideal 308329, lino, 174.9 grains, sized 0.310” in Saeco lubrisizer.
Powder – Varget, 32.5 grains. I chose this charge by using Virg Edwards record-setting load of 30.6 grs. of Varget in his .308 with a slightly heavier bullet, and increasing it to allow for the .30-06 powder capacity of the 7.5x55. Note: I am not recommending this or any other load. I am just reporting what happened with it in my rifle.
Primer - F-210. What I had lots of on hand.
Case - Winchester .284 case opened to take .30 bullets, simply by running the cases into an RCBS 7.5 Swiss sizing die with a tapered expander ball.
Anyone can, with a bit of effort & patience, taper an expander ball with a file, a grinder, course emery cloth, or an India stone.
Be sure to check your brass for overall length. I just run mine into an RCBS file-trim die, and use the file if necessary.
Lube(s) - I tried two, 40 rounds with Thompson’s Blue Angel and 20 rounds with Lyman’s Super-Moly.
Seating - This bullet chambered very nicely, with the bullet seated so that 0.010” of the 0.083” high Hornady gas check, lot 394, protrudes below the case neck. This leaves 0.073” of the gas check up in the case neck, so “Noooooo...Problem” with the bullet being exposed to raw, hot powder gas upon ignition.
Seated at this depth, the cartridge also feeds nicely through my magazine, and can be ejected without firing, and without damaging the bullet or pulling it from the case. (It doesn’t “stick” in the bore if you eject it unfired.)
Results
It took me approximately 10 rounds at 100 yards to get the sights set appropriately for shooting at a nice big 100-yard M.L.R.A. Rifle Target. The sights are the issue K-31 open “U” tangent rear sight, and adjustable (by drifting) blade front. This cast load shoots approximately 4” high at 100 yards with the sights set on the 100-yard notch. Nothing lower is available on this sight, but, by using a six-o’clock hold on the black, the groups are exactly 1” above dead center in the bull.
In my rifle, this load also shoots approximately 8” right from my jacketed load of 150-gr. bullets and 46 grains of IMR 4320. The front sight is drift-adjustable on a diagonal, however, and with it drifted until the front of the blade is just even with the front of the sight base, it is dead-on for windage.
As for groups, with two people alternating shooting the rifle in no particular sequence, the Thompson’s Blue Angel rounds were putting 5 shots into groups which averaged well under two inches. The best group was 1-3/16”.
Unlike what I expected, the Lyman Super-Moly did slightly better, with a smallest 5-shot group of 1-1/8” and an average of about 1-5/16”.
As I said, I have old eyes. Much of the time I could really not see the rear sight. I did use a rear sandbag and one of the cheapo Midway plastic front rests. The trigger on my rifle is a very nice, original military two-stage, with the second stage estimated at 2.5-3.0 lbs.
Many thanks to the Lister who brought up this subject. This load shoots so well I am not sure I want to test any of the other bullets I cast for the purpose. I am also going to reserve this rifle exclusively for “lead-only” from now on.
And, now, I plan to buy a B-Square mount so I can put a “scout-style” scope where the rear sight now sits. That way I can always put the original military rear sight back on if I want/need to. With a decent scope, and this load, this gun should be fully competitive in Production Class if it continues to shoot this way. I figure the ability to see what I’m aiming at should take at least another 1/2” or more off the groups.
By the way, this is one of the most pointy, long-nosed cast bullets I have ever seen. Without the boat-tail, it is slightly longer-nose, and slightly more pointy that the military ball 174 gr. M-1.
Neck Sizing the 7.5x55mm Schmidt-Rubin
Today was the second day I loaded ammunition during the day and shot it the same day in my new K-31 from Simpson. I hate to load ammo during the day when it is sunny out because usually those days are rare in winter and spring in western Washington.
I have had trouble with my reloads for my first K-31 and read references to problems others have had with their Lee 7.5x55 Schmidt-Rubin FL sizing die. So today I was determined to try neck sizing some brass. I’d read of others who had used Lee Collet dies with washers around the base of some round to extend the ‘reach’ of the collet. I have some Lee .308 Winchester Collet dies (7.62x51) so figured that if I could add at least 4mm to the distance above the base of the shell holder, I could use that die to neck size the Swiss stuff.
Before I cleaned off my lathe to turn an extender, I thought I’d see if I had any real washers that might work. Because I am the type of guy that buys boxes of 100 washers for most sizes between #4 and 1/2”, I found some 7/16” nominal ID washers that fit closely to the body of the case at the shell holder. Each washer was about 0.117” inch thick with a 0.497” diameter hole and an OD of 1.275”. So two washers stacked up to about 4.7mm, thus extending the neck sizing distance to work with a cartridge length of 55mm rather than the 51mm it was made for.
This was good except the washers were too large on one side to allow the case to fit in the shell holder with-out touching the inside of the reloading press. So I had to hacksaw about 3/8” off one side. That got them to fit.
Next I found the strain of getting the collet die to neck size was too tough for my screwed down reloading presses (a Lyman AccuPress and also a Lyman Spar-T) so I put the dies in the Lee Hand Press. That worked!
It looked like the neck sizing reduced the OD of the neck only about 0.007” but that was enough to make a sliding fit .30-30 bullet not slide in all the way. I then used a .30 cal. Lyman M-die to bell-mouth the cases for use with cast bullets.
Now to deprime the cases: The Lee 7.62x51 Collet die decapper wasn’t long enough and the cases wouldn’t fit into a 6.5x55 die so eventually I found my Lee .30-06 collet die and used it to deprime the brass. I next used the Lee Autoprime to prime the brass and was ready to reload.
All loads here were with 16.0 grains of 2400. I used some commercially cast 150 grain RNFP gas checked 0.308” .30-30 bullets which shot well but didn’t reliably feed good as well as some of the Lasercast 170 grain 0.310” w/o gas checks which shot very poorly. Of home cast bullets I used some Lyman 311359 with gas checks which were sized to 0.308” and weighed 120.1 grains. These fed well and 3 of 5 shots went into less than 1” grouping. I also used some Lyman 311465 sized to 0.309 weighing 128.9 grains.
I realize that to many of you those groups would be considered pretty poor but to me, they are some of the better ones, showing that the Swiss rifles are among the most accurate of military rifles. I had two fun days out of all this.
Today was the second day I loaded ammunition during the day and shot it the same day in my new K-31 from Simpson. I hate to load ammo during the day when it is sunny out because usually those days are rare in winter and spring in western Washington.
I have had trouble with my reloads for my first K-31 and read references to problems others have had with their Lee 7.5x55 Schmidt-Rubin FL sizing die. So today I was determined to try neck sizing some brass. I’d read of others who had used Lee Collet dies with washers around the base of some round to extend the ‘reach’ of the collet. I have some Lee .308 Winchester Collet dies (7.62x51) so figured that if I could add at least 4mm to the distance above the base of the shell holder, I could use that die to neck size the Swiss stuff.
Before I cleaned off my lathe to turn an extender, I thought I’d see if I had any real washers that might work. Because I am the type of guy that buys boxes of 100 washers for most sizes between #4 and 1/2”, I found some 7/16” nominal ID washers that fit closely to the body of the case at the shell holder. Each washer was about 0.117” inch thick with a 0.497” diameter hole and an OD of 1.275”. So two washers stacked up to about 4.7mm, thus extending the neck sizing distance to work with a cartridge length of 55mm rather than the 51mm it was made for.
This was good except the washers were too large on one side to allow the case to fit in the shell holder with-out touching the inside of the reloading press. So I had to hacksaw about 3/8” off one side. That got them to fit.
Next I found the strain of getting the collet die to neck size was too tough for my screwed down reloading presses (a Lyman AccuPress and also a Lyman Spar-T) so I put the dies in the Lee Hand Press. That worked!
It looked like the neck sizing reduced the OD of the neck only about 0.007” but that was enough to make a sliding fit .30-30 bullet not slide in all the way. I then used a .30 cal. Lyman M-die to bell-mouth the cases for use with cast bullets.
Now to deprime the cases: The Lee 7.62x51 Collet die decapper wasn’t long enough and the cases wouldn’t fit into a 6.5x55 die so eventually I found my Lee .30-06 collet die and used it to deprime the brass. I next used the Lee Autoprime to prime the brass and was ready to reload.
All loads here were with 16.0 grains of 2400. I used some commercially cast 150 grain RNFP gas checked 0.308” .30-30 bullets which shot well but didn’t reliably feed good as well as some of the Lasercast 170 grain 0.310” w/o gas checks which shot very poorly. Of home cast bullets I used some Lyman 311359 with gas checks which were sized to 0.308” and weighed 120.1 grains. These fed well and 3 of 5 shots went into less than 1” grouping. I also used some Lyman 311465 sized to 0.309 weighing 128.9 grains.
I realize that to many of you those groups would be considered pretty poor but to me, they are some of the better ones, showing that the Swiss rifles are among the most accurate of military rifles. I had two fun days out of all this.