[mech481]

Things seem to have gone quite on 8x58RD rolling blocks so just to stir the pot has anyone done any load development since the post on Norma loads, pressures, etc. etc.
Would be very interested as my cases should be here this week and will start to work up a few loads.
And would like to pick the more experienxed 8x58RD shooter brains on this forum.

 

[jhrosier]

I have been working up some loads with a 205 gr cast bullet.
It is still a work in progress, so I won't bore you with all the details.
I have tried several powders and am getting the best results with Unique.
I am trying to stay close to the 28.6Kpsi suggested as maximum in the post in the sticky at the top of the forum.
I have been able to finally get consistent ignition and velocities, but my bullets were a little too soft and accuracy was not acceptable.
I have cast some harder bullets and should be posting the load developement observations and data soon.
There is a lot more information than I can put into a quick reply, but consider using Unique under a cast bullet and work the load up to just under 1500fps to start. You should be OK to start with 12grs. Unique and a bullet somewhere close to 200 grs.
From what I have seen so far, I don't think that the 8x58RD rolling block rifles are likely to shoot sub-moa with any safe load, but I believe that 1-2 moa is do-able.

Jack

 

[mech481]

8x58RD loads

I thought there might be lots of replies to this since the re-thought on safe loads, I read on another forum about a shooter using a slow powder with good results ( reloader 22 ) any comments gents.

 

[jhrosier]

I expected a little more response, myself. I'm very curious to hear what other folks have been doing and what has worked.
As a follow up to my earlier post, I shot the gun today with bullets cast from 50/50 lino/ww. The groups shrank down to about 2moa, average. I had a couple of 3 or 4 shot groups less than 1moa, with flyers to open them up. I believe that the gun may be capable of near-moa accuracy, however, I have reached the limit of how well I can use open sights.
I have to make a decision about making or buying some sort of aperature sight.
There are two factors to consider.
First, I am hesitant about modifying the gun by drilling holes to mount another sight.
Second, a decent tang sight will require the expenditure of significant funds, which I do not have handy.

It has occured to me, that I could machine a scope base that would clamp on the barrel and mount a long eye relief scope.

I'm open to suggestions regarding the sights.

As to using slower burning powders, I've had so much trouble getting good ignition, even with Unique, that I pretty much rejected the idea. Besides, with the current cost of powder, it seems like and expensive way to get a load with filler. Is there any reliable data regarding pressures with slower powders?

Jack

 

[NiklasP]

I am surprised that you would have any trouble at all getting Unique to ignite consistantly with any of the standard rifle primers, such as Remington, Winchester, CCI, etc. I would suspect that you have not been consistant in getting the powder fully back in the case, OR, that you are encountering a common problem with these guns, that is, that you have to get muzzle velocities up to a minimum velocity before bullets quit tumbling. For most suitable bullets in my gun that minimum has been 1300-1350 fps. For some bullets I have yet to find a load that does not give tumbling bullets -- granted, these poorly performing bullets are undersized, being 0,321-0,323, that is, 32-40 or 8X57 Mauser caset bullets. I have yet to try any mantled bullets.

I have been using Reloader 22 for at least 20 years in 7X57 and 7X57R. There are lots of data for those "twins" and especially for even larger capacity cartriges. Some of those loads were full case, compressed and never had a problem with ignition. A simple extrapolation from cartridges like 7X57 to 8X58RD, based on difference in case volumes indicates that moderate loads of Reloader 22 will have chamber pressures below 30.000 psi. I go even a bit lower than this in a rather tight chambered 8X58RD with 210 grain cast GC bullets. Velocities are quite low, about 1750 FPS from 33 inch barrels, cases fall out of chamber, groups are as good as I can shoot with the military sights, that is about 3-4 inches at 150 meters.

FYI, burn rate for Reloader 22 is very close to that of Norma MRP.

I think the reason you are not getting more responses is that what most (all?) of us know has already been posted on threads extant on this board.

Niklas

 

[jhrosier]

I am surprised that you would have any trouble at all getting Unique to ignite consistantly with any of the standard rifle primers, such as Remington, Winchester, CCI, etc. I would suspect that you have not been consistant in getting the powder fully back in the case,

Thanks Niklas,
You are quite correct about the powder being in the back of the case.
When I tap the case on the bench to settle the powder to the back and then chamber it carefully, the ignition problems go away. Although many advise against using anything on top of the powder, I put a 2gr. piece of dacron fiber (quilt batting) in the case and press it down tight against the powder. The ignition of the powder is now very consistent. The extreme spread and standard deviation of the velocity immediately dropped to about 1/3 of the values without the filler.

.., that you are encountering a common problem with these guns, that is, that you have to get muzzle velocities up to a minimum velocity before bullets quit tumbling. For most suitable bullets in my gun that minimum has been 1300-1350 fps.

I have checked my targets at 25,50 and 100 yards and see no sign of the bullets starting to tumble. My velocities are just inder 1500 fps.

For some bullets I have yet to find a load that does not give tumbling bullets -- granted, these poorly performing bullets are undersized, being 0,321-0,323, that is, 32-40 or 8X57 Mauser caset bullets. I have yet to try any mantled bullets.

I measured the bore of my rolling block at the muzzzle and found it to be .329" . I am using a Lee bullet mould designed for the 8x56 Hungarian. It casts a 205gr. round nose, gas checked bullet at .330" to .333", depending on alloy. I am sizing thesse to .329 with the Lee push through sizer and lubing with Lee Liquid Alox. These bullets shoot much better when cast of a hard alloy than a soft alloy. I would be very interested to know how many of these rifles have a .329" rather than .323" bore. I think that you could maybe get away with an undersized jacketed bullet, but this is not an option when using cast bullets.

I have been using Reloader 22 for at least 20 years in 7X57 and 7X57R. There are lots of data for those "twins" and especially for even larger capacity cartriges. Some of those loads were full case, compressed and never had a problem with ignition. A simple extrapolation from cartridges like 7X57 to 8X58RD, based on difference in case volumes indicates that moderate loads of Reloader 22 will have chamber pressures below 30.000 psi. I go even a bit lower than this in a rather tight chambered 8X58RD with 210 grain cast GC bullets. Velocities are quite low, about 1750 FPS from 33 inch barrels, cases fall out of chamber, groups are as good as I can shoot with the military sights, that is about 3-4 inches at 150 meters.

FYI, burn rate for Reloader 22 is very close to that of Norma MRP.

I think the reason you are not getting more responses is that what most (all?) of us know has already been posted on threads extant on this board.

Niklas

Thanks for the information on Reloader22 powder. I still question the economy of using powder as a filler, considering the recent price increases on powder.

If anyone has had good results with XMP5744, I would be interested. I tried it once but found that it was very dirty, leaving the case necks and bore coated with heavy residue.

Jack

 

[NiklasP]

Jack,

For whatever it might be worth, I hear from fellow shooters that XMP5744 can be very dirty or rather clean burning, depending on amount of powder used in a given load -- don't know any details at all. I don't use it because I have plenty of other powders left over from previous activities. The powder I have most of, bought years ago at nice discount, is Reloader 22.

I have seen reports of some 8X58RD chambered rolling blocks having bores as large as yours. As I recall, the bore on mine is 0,324 or 0,325. GC bullets I am using are 0,324.

Niklas

 

[gunboat]

I just found this thread and thought I'd share a couple things. Jack, like yours, my RB groove diameter measures very close to .330 diameter. I also cast bullets using the 8X56 Hungarian mold. Rather than using gas checks, I machined a bit off the mold to get rid of the rebated part of the bullet, leaving it flat based and weighing a bit under 200 gr. using WW. I use 22 gr of IMR 4198 with that bullet and use a bit of cotton to hold the powder back against the primer. I'll have to check my notes to see what kind of velocity I'm getting.

I also shoot a 150 gr JSP bullet, also made for the 8x56 Hungarian. I use 40 gr of IMR 4895 and get around 2000 fps.

I have used .323 diameter jacketed bullets but I was concerned about gas cutting. I once deliberately used a very small charge to drive a 200 gr .323 JSP bullet a few inches into the rifling. I could see daylight at each of the grooves.

By the way, when I first bought my Swede RB years ago, I also bought a box of 8X58RD from Ammodepot. I fired only one. It was very hard to open the rifle after that shot. I pulled the bullet on another round and measured 52 gr of some powder that looked like 4895. Apparently, Ammodepot had loaded the ammo nearly to the levels listed in Cartridges of the World. I guess that was a good proof load for my rifle. Nothing got sprung or jugged and the action is still tight, thankfully. I ended up pulling all the bullets and dumping the powder and just using the brass. I don't see loaded 8X58RD on Ammodepot's website anymore.

Tom

 

[Smokepole50]

XMP5744 powder

I have been doing some load development with this AA 5744 powder. I have been shooting 185gr Rem Core-loks with 24gr of the 5744 powder. It pushes the bullets at approx 1700fps out of my .324 barrel. I have not fired them at any distance so I do not know if they will tumble at ranges further the 10 yards. I have mostly been fire forming my brass to my chamber with this load. I started off with 20 gr and have loaded up to 26 grains of the AA 5744. This powder ignites very well with LR primers and does not need to be tilted back to seat the powder against the primer. Also, according to AA, it will leave a residue in the barrel untill you go past the 18,000 PSI range. Be VERY CAREFUL with this fast powder. I would not go over 26gr with jacketed bullets without extensive testing with a chronograph. 26gr pushed the 185gr Core-lok up to 1850-1900 fps.

I have received some 190gr GC lead bullets that I plan on shooting after hunting season. I also plan to try and work up a N140 jacketed bullet loading. As soon as Sportsmans Warehouse gets the powder in I'm gonna start working up a load with the 185 Rem bullets.

I have also been working with Bruce Bertram, owner of Bertram Brass at correcting the problems with there cases. Bruce has made some good progress and the cases he sent me to test were closer to the spec. size needed.

Smokepole50

 

[jhrosier]

Smokepole,
I will be very interested to hear your results with the 5744 and cast boolits.

I doubt that I will get much more serious shooting done this year. The temps in New England don't agree with me at all in the winter, for shooting. Anything less than 40 degrees and I can't feel my fingers, anything over is likely to be uncommon for a few months.
The break will give me time to stock up on boolits anyhow. I want to try water dropping some WW to save my stock of lino. I'm starting to get neck splits after four loadings because the CH4D dies are working the case necks too much. I think that I will spring for a set of Lee custom collet sizing dies. I also see some merit in mounting a tang sight on the roller but they certainly aren't giving those away!

I hope that Bertram gets the problems with the brass straightened out. I'm perfectly satisfied with the reformed 8x56 Hungarian cases for the 8x58RD, myself but there are a couple of other calibers that they make that interest me.

gunboat,
Does your RB have a very long throat? Mine is so long that only the gascheck would be in the case if I seated out to touch the rifling. I seem to need a very hard boolit to survive the 1/2" jump to the rifling.

Jack

 

[sbhva]

This message will serve as a "teaser". A very close friend of mine has been in contact with the powers that be at Norma and I will soon have some info to share here regarding the old Norma loads for this cartridge. This would be the "civilian" load that was sold in Sweden for all those sporterized rolling block moose rifles, not a military loading for the Krag rifle.

Stay tuned.

 

[gunboat]

Jack,
I just measured the throat on my RB. The way I seat them, the 200 gr cast bullet has to travel .470 inch before it contacts the rifling. That means the base of the bullet is about .200 inch out past the case mouth before the front end engages the rifling. Now, I'm using formed 45-70 brass which is 2.280 OAL, about what real 8X58RD brass should be, so I can't decrease my "free bore" distance any more.

I did check my notes on MV. My 22gr IMR 4198 load gives 1585 fps with +/-4 fps in 3 shots.

I had 5 loaded rounds left from almost a year ago so I shot them today. Results are below. First two shots on the left were me resting on a table. Three shot group to the right was using a sandbag rest to take me out of the equation. Range was 50 yards.

The bullet is my bob-tailed .329 out of wheel weights. Lube is 50/50 beeswax and Crisco. Dirty brass needs to be tumbled.

My rifle is shown. I added the sporter sights as it had none when I bought it.

Tom