Cast Bullets in the 6.5x55 Swedish Mauser

Glen

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Staff member
#1
Cast Bullets in the 6.5x55 Swedish Mauser

By Glen E. Fryxell

In 1894, the Swedish Army adopted a new bolt-action rifle chambered for a new 6.5x55 cartridge. This cartridge would serve until the early 1960s, and would be used by sportsmen (both hunters and long-range target shooters) well into the 21st century. The original ammunition for the 6.5x55 had 160 grain RN at about 2400 fps. This was later changed to a 139-140 grain spitzer at about 2600 fps. One way to think of this cartridge was a 19th century version of the .270 Winchester, with an extra helping of sectional density. It was definitely ahead of its time in the 1890s.

Military 6.5x55 barrels were made with a 1 in 20 cm twist (which amounts to about 1 turn in 7 ¾”) because of the long slender bullets used. Like most military rifles of this vintage, throats tend to be long (0.500” or more), and somewhat oversized (.267+”) to insure reliable feeding/chambering on the battlefield. Nominal groove and bore dimensions are .264” and .256”, but in reality these dimensions vary widely (hence the stock discs installed in the buttstocks of most Swedish Mausers reporting the dimensions and the degree of bore erosion -- http://candrsenal.com/tip-how-to-read-swedish-mauser-stock-disks/ ).

Norway also used the 6.5x55 in some of its Krag-Jorgensen rifles. This rifle has only 1 locking lug, which works just fine at about 45,000 CUP, but does not have the strength of a Springfield or a K98 Mauser hence the need to keep factory 6.5x55 ammo pressures down.

I have long been a fan of the 6.5mm bore because of the excellent performance (and bullet selection), and I am of Swedish descent, so it’s no surprise that the 6.5x55 Swedish Mauser cartridge has long piqued my interest. Many years ago, one of our local sporting goods stores brought in a truckload of Swedish Mauser rifles and was selling them for very friendly prices, so I picked one up (made in 1906). A few years later, my darling wife bought me a Swedish Mauser Target Rifle (with the diopter target sights) for an anniversary present (it was made in 1905).

Inspection of the stock discs on these rifles reveals that the infantry rifle is marked to have a 6.50mm bore (.256”) and the target rifle 6.49mm bore (also about .256”). Groove diameter on rifles like these tends to vary somewhat and it’s not unusual for them to run a bit on the large side.

For many years, these two rifles were my only outlet for shooting the 6.5x55 cartridge. Needless to say, I wanted to play with cast bullets in them, so I bought a 2-cavity Lyman 266469 140 grain Loverin GC-RN mould, and started casting bullets. My friend Charles Graff advised that I might find better results if I kept velocities down to about 1600 fps or so because of the fast twist. I quickly learned that cast bullets sized .264” did not shoot well, so I bought a .266” sizer die. Ahhh, much better. The Lyman 266469 drops from my mould at about .266”, with a .256” bore riding nose. While these guns were not producing groups that were one ragged hole, I had no trouble producing 10-shot groups at 50 yards that were 1 ¼” (or less) with the diopter target sights. I played around with a variety of loads and settled on 16.0 grains of 4198 for right at 1600 fps from the full-length rifles (10.0 grains of Red Dot for 1400 fps also makes a very fun plinking load). Higher velocities were possible, but generally opened up group sizes.

65x55 with Lyman 266469.jpg
The 6.5x55 with the Loverin bullet

About this time, I ran across a Lyman 266469 HP mould, and snapped it up. I tried a few of these in these two Swedish Mausers with the 4198 load and they shot OK, but not as well as the solid version (unusual, most HP bullets generally tend to shoot as well or better than their solid counterparts). I didn’t really look in to why since I wasn’t really planning on hunting with these long rifles, I just assumed it probably had something to do with how the nose fit the throat, or leade (more on this later…).

Then, a few years later, I bought the “project gun” (I suspect that many of you have also had “a project gun” at one time or another). I was over on the Olympic Peninsula, visiting a buddy of mine, and doing a little hunting for coastal blacktailed deer. It was raining that day, so we came down out of the mountains to grab a burger and some hot coffee for lunch, then stop into the local gun shop to browse for a while. We had looked over everything on the floor racks and behind the counter, and talked to the owner, and dug through the ubiquitous used holster bin and the “reduced for quick sale box”, and were on our way out of the store when I looked up at the guns hanging on the wall, up near the ceiling, over by the front door. There were a handful of the usual guns up there (e.g. a pump-action 12-gauge, a semi-auto .22, a hardware store-brand .30-30, etc.), but there was one that I didn’t immediately recognize. It was labelled with a 3”x5” card that simply read “6.5x55” along with a price that was well under $200. I asked to look at it. It turned out to be a Swedish Mauser Carbine that someone had mounted in a badly mismatched stock – it had a huge Monte Carlo cheekpiece (that was so large that you could not get your eye down low enough to line up the sights), and the length of pull was about right for Paul Bunyan. It was pretty clear that somebody had a barreled action, and had slapped it into this stock in order to sell it (and obviously had never shot it). I looked it over – the barreled action was in pretty good shape, and the bore looked very good. The wood was nothing special, but it was a sound piece of straight-grained walnut, and I figured I could whittle it down and make it work. The price was right, so I bought it.

Well, I got it home and found out that the stock had been inletted for something entirely different, and whoever had just dug away enough wood to get the 96 action into the wood and out the door. There were large gaps in the inletting where the action touched nothing at all. I reshaped and refinished the stock (which turned out rather nicely, if I do say so myself), and then turned my attention to epoxy bedding the action. Long story short – I poured a lot of epoxy (and brass shim stock) into that stock and never did get the carbine to group worth beans, with either cast or jacketed bullets. Proper bedding is important.

A buddy of mine had a spare Swedish Mauser carbine stock lying around from one of his previous projects, and made me a good deal on it. I mounted the barreled action and verified that the carbine would group so stocked, then started to work sporterizing the military stock. Next, I drilled and tapped the receiver for a Lyman Model 57 peep sight. Thus, the Swedish Truck Gun (STG) was born.

Swedish Mauser rear sight mounted 2.jpg
The Swedish Truck Gun and its new rear sight.

My vision for the STG was a gun that I could take over to the Olympic Peninsula to hunt blacktailed deer with my buddy. The woods are thick, so ranges are short (shots are typically 25-50 yards). These deer are small (100-110 lbs), and don’t take a lot to put down, but since the woods are thick (and commonly rainy) you don’t want them running off, and making for a difficult tracking job, so a rapidly expanding cast HP would be good. In addition, there are a fair number of grouse in those woods, and you never know when an opportunity will pop up to pot one for dinner, so it’s good to be prepared to head-shoot grouse at close range.

The throat on the STG starts at about .270” and tapers down to about .267”, and it’s over .500” long, so there is plenty of room to seat bullets long. A number of jacketed bullets shot poorly from this oversized throat (most notably those that were .263” in diameter or those that were 2 diameter bullets, e.g. .256” noses, on top of .263/.264” bases). The two jacketed bullets that shot reasonably well were the Hornady 140 grain SP (at about 2500 fps) and the Hornady 160 grain .264” RN (at about 2300 fps). These bullets have long .264” bearing surfaces that help with alignment in the oversized throat.

Not surprisingly, cast bullets need to be oversized to shoot well in this oversized throat. I tried the Lyman 266469, sized .266” (which had shot well in the two full-length rifles), and it didn’t do so well in the Swedish Truck Gun. I had Mountain Molds (http://mountainmolds.com/) make me a .268” diameter 140 grain bullet that I designed using the RCBS 30-180-FN as inspiration. I also had a friend of mine make me a .268” sizer die and he produced a thing of beauty. Now we were getting somewhere! Groups shrank down to very respectable sizes, and with a little work I settled on 16.0 grains of 4227 for 1580 fps, which printed dime-sized groups at 25 yards (for head shooting grouse), and printed about an inch lower than the full throttle 160 grain RN load at 2300 fps. The STG was now starting to get happy.

STG and MM 268 140 4227b.jpg
Mountain Molds group.

During the time that I was wrestling with the stock demons with the STG, I also managed to talk a buddy of mine out of his Remington 700 Classic in 6.5x55. I was particularly interested in this gun because Remington used a somewhat slower 1 in 9” twist when they made this gun, and I suspected that this slower twist would be friendlier to cast bullets, and perhaps allow better accuracy at higher velocities. Not surprisingly, it also has a somewhat tighter (and shorter) throat, and the groove/bore diameters appear to be much closer to spec on this barrel than on the military Swedes described above. The Lyman 266469 Loverin bullet, sized .266” and loaded over 26.5 grains of 4895, shoots very well in this gun at 1900+ fps (once again, the 266469 HP sized .266” did not shoot as well as the solid).

Rem 700 Classic 65x55 cast test.jpg
The Remington 700 Classic and Lyman 266469 group.

In an effort to see if the MM 140 FP bullet would also work at higher velocities in the STG, a series of loads were worked up with the MM 140 sized .268” with 4895. Accuracy started going south at about 22 grains, and by 23.5 grains of 4895 shots were scattered all over the paper with keyholes being observed. Clearly, the faster twist and fatter throat of the STG were less accommodating of higher velocities than those of the Remington 700.


NOE 270469

Al Nelson (a Swede himself) over at NOE (http://noebulletmolds.com/; (801) 377 7289) must have heard the gnashing of teeth of Swedish Mauser shooters/casters because he makes the Lyman 266469 design in moulds that produce a nominal .270” diameter bullets. In the hopes of keeping the STG well stocked in cast bullets, I ordered a 5-cavity gang mould.

The mould arrived promptly – it is truly a thing of beauty, and casts like a dream. Bullets dropped from my mould with a .262” nose, first two driving bands are .267”, next two driving bands are .269”, and the last two are .271”. These dimensions are ideally suited to the oversized (and slightly conical) throat of the Swedish Truck Gun.

NOE 270 149 RN.jpg
The NOE mould.

However, the GC shank was skinny on my bullets (.244”). I thought this was odd as the machine drawing on the NOE website specified .250/.253” for the GC shank (which would be perfect for what I want to do), but I went ahead and loaded a test batch of ammo sized .268”. The Hornady GCs were pretty loose, so I seated this first round of test loads long to keep the GCs well within in the cartridge neck to hold them in place. A test round chambered just fine, but then left the bullet stuck in the throat when I opened the action (I had seated them just a little bit too long….). Accuracy testing in the Swedish Truck Gun revealed that these bullets shot MUCH better than the .266” Lyman 266469s had. OK, we’re making progress. I like progress.

But what to do about the undersized GC shank? Well, that turned out to be a fairly easy fix. I’m sure I could have packaged it up and shipped it back to Al, and I’m sure he would have fixed it for me, but I was impatient and felt up to the job. I took a short piece (roughly 2” long) of .250” round stock and chucked it up in my drill press, and adjusted the height of the table so that the end of this round stock only went deep enough into the cavities to contact the GC shank. Then I wiped the tip of the “lap” with some Grade A (280 grit) Clover Compound, and adjusted the belts on my drill press to its slowest speed (~160 rpm). I closed the mould around this lap on each cavity, refreshing the lapping compound between cavities, and then went back and did a second pass as a polishing step. This opened up the GC shanks sufficiently (.247-.248”, after shrinkage) so that now the Hornady GCs crimp on very nicely, and stay put. These bullets, sized .268”, shot better (OK, but not great) in the STG with 16.0 grains of 4227 (~1600 fps).

I had a spare .266” sizer die sitting around that I packaged up and sent to my friend Erik Ohlen (http://www.hollowpointmold.com/; (541)738-2479) and he honed it out to .270”. for me. As an aside, if you are looking for an odd-ball sized sizer die, this is an excellent option for getting exactly what you want. Erik has done several sizer dies for me over the years, and has nailed each one spot-on. This die came back producing bullets that were .270” on the nose. The NOE 270469, sized .270”, and loaded over 16.0 grains of 4227, shot superbly out of the Swedish Truck Gun. This is now my go to, general purpose plinking/target load for the STG. With a 5-cavity mould, I can mass-produce this bullet in quantity, I can now size it to fit the gun, and it shoots to precisely where I point it. The STG is getting happier.

STG with NOE 270469.jpg
The STG with the NOE 270469 sized .270" group.

This proper throat fit just might also allow for higher velocities. In an effort to see if the additional bearing surface of the NOE 270469 might also allow higher velocities in the STG, test loads were assembled with the NOE 270469 sized .268” and .270” with 26.5 grains of 4895 (~1900 fps, the same powder charge that shot well in the Remington 700 above). The .268” bullets looked like there might be some promise, but the .270” bullets were all over the paper (and bullets were starting to keyhole). Good throat alignment is clearly valuable to the assembly of accurate cast bullet loads, but a fast twist barrel can still be very hard on a cast bullet. Quick review -- at 1600 fps, with the 1 in 7 ¾” twist of the Swedish Mauser, these bullets are spinning at approximately 149,000 rpm; at 1900 fps, they are spinning at approximately 177,000 rpm. From the 1 in 9” twist Rem 700, bullets at 1900 fps are spinning 152,000 rpm. Keep in mind that these cast bullets are getting accelerated, not just linearly, but also rotationally, from a dead stand-still up to these rotational speeds in less than 20” of barrel, and in just a few milliseconds. Lead alloys tend to be pretty soft and this rotational acceleration places a significant strain on a cast bullet, especially since it is being focused on only about .004” of the bullet metal where the lands are “biting” it. If the alloy is overcome and fails, it leads to stripping, which leads to gas leakage, leading to bullet yaw, and ultimately to poor accuracy. The appearance of oblong bullet holes can be an indication that these issues are starting to creep into the picture – always something to look for when shooting cast bullets in fast twist barrels.


The 266469 HP revisited

The success with these two over-sized cast bullets (the MM and NOE) led me to go back and take a closer look at the Lyman 266469 HP. I found some that I had cast several years ago, and miked them -- the first driving band is .269”, and all the rest are .272” as-cast. I can’t say for sure what happened before, but when sizing long, skinny bullets down excessively, sometimes they can get bent ever-so-slightly, and I’m guessing that is why I was getting poor accuracy with these HP bullets when sizing them .264” or .266”.

Anyway, I took a batch of these 266469 HPs and sized them .268” and loaded them over 16.0 grains of 4227. As with the NOE 270469s described above, these .268” HPs shot better, OK, but not great. Given the success observed with the NOE 270469s sized .270”, I next took a batch of the Lyman 266469 HPs and sized them .270” and once again loaded them over 16.0 grains of 4227. These loads grouped very well indeed, and would make a fine hunting load for animals up to maybe ~150 lbs. Expansion testing in 1-gallon milk jugs filled with water revealed that expansion is positive for the 266469 HP at this speed (~1600 fps). 1600 fps is a very comfortable speed for a cast HP as it provides for rapid expansion of the HP, but without the hand grenade like explosions seen at higher velocities. The STG is now very happy.

STG with Lyman 266469 HP sized 270.jpg
The STG with the NOE 270469 sized .270" group.

Just out of curiosity, I wanted to see if these “fat HPs” could be driven faster, so I sized these 266469 HPs .270” to get full support in the throat during engraving, and loaded them over 26.5 grains of 4895 for ~1900 fps. Groups opened up notably and bullet holes were starting to get oblong – just like before.

Conclusions

Cast bullets need to be sized at least .268” for best accuracy in the over-sized throats of Swedish Mausers, and .270” works even better in the STG. More recent commercial barrels (e.g. the Remington 700) may have tighter throats and bores and do well with .266” cast bullets.

Moderate velocities (e.g. about 1600 fps) seem to work best in the fast twist (1 in 7 ¾”) of the Swedish Mausers. Higher velocities tend to open up groups and commonly show signs of keyholing (due to stripping?). Some commercial barrels e.g. Remington 700) have a slower twist (1 in 9”) and will shoot cast bullets well at higher velocities (e.g. 1900 fps).

The Mountain Molds 140 GC-FP is the best (most accurate) cast bullet in my guns. The NOE version of the Loverin bullet (the 270469) fits the over-sized throats of the Swedish Mausers very well, and when sized .270” it is a close second to the MM bullet.

The Loverin bullet (Lyman 266469), sized .266”, also shoots reasonably well in my full-length Swedish Mauser rifles, when loaded to moderate velocities (e.g. 1400-1600 fps). But the STG has a somewhat fatter throat and groups terribly with this cast bullet at .266”. All of these Swedish Mausers do better with the oversized NOE 270469. Lyman 266469 moulds that produced fatter bullets would probably do just fine in the Swedish Mausers, and the .266” 266469s shoots very nicely in my Rem 700 6.5x55.

The Lyman 266469 HP, sized .270” and loaded to ~1600 fps, looks like it has real potential as a hunting load for smaller deer, antelope, coyote, etc. sized game in the Swedish Truck Gun.
 

Glen

Moderator
Staff member
#3
Some of the numbers from the MM bullet:
forward driving band (as-cast) -- .267"
all other driving bands (as-cast) -- .269"
nose -- .425" long
nose diameter -- .260"
meplat -- 73%
 
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Glen

Moderator
Staff member
#4
PS -- The Hornady crimp-on GCs are about .010" thick, and work just fine on all of these cast bullets when sized .268" However, on the NOE 270469s, with the slightly narrower GC shank, the Hornady GCs are still a little loose when sized .270". The aluminum GCs from Vulcan Checks are available in multiple thicknesses, including .013" and .0145", and these thicker GCs work beautifully on the NOE bullet.