Cast loads in a Yugo M48....help !

[bcp477]

I have been trying various cast loads in my M48 (7.92 x 57JS) for some time....with no success. It seems that the barrel simply doesn't like cast bullets, though it shoots (many) jacketed ones very well. The bore of my M48 is far from new....and has a small amount of pitting, though not much. I keep it very clean and only shoot handloads. The bore dimension I got after slugging the barrel, some time ago, was .3233". I have checked the throat area, with a borrowed borescope...and no unusual amount of erosion is in evidence. I have been experimenting most recently with Alliant Unique and 170 grain, .324" sized flat-nosed bullets. I do not cast my own bullets and have no desire to do this (I have no suitable place in my home for this, anyway)....so any bullets I try will be purchased. I have, in the past, tried bullets (also sized .324") from several other sources, but they all seemed to be from the same type of mold, as they all appeared to be identical. I have also tried several different powders...and a myriad of charge weights....both with and without dacron filler. I have, of course, read the article attached to this website regarding cast bullet loads in military rifles....and I have tried to follow it's suggestions closely. In all cases, however, no matter which powder or charge I've tried, accuracy has been terrible...or more specifically, nonexistant. The results I get from jacketed bullets with moderate charges are routinely sub 2 MOA, using iron sights. The "universal" 16 grains of 2400, with these bullets, in my rifle.... will seldom place any shots on paper, even at 50 yards. "Group size" is a term that could not be said to apply here. I am currently experimenting with Unique....and I have tried 8 through 12 grains, with no luck.

My question is, have any of you gentlemen encountered a rifle which performs similarly to mine...that is, it just doesn't seem to like cast bullets, no matter the powder or load (eventhough it does very well with jacketed bullets)??? Any suggestions as to what to try next ??? Since I am not in position to cast my own bullets, I will have to rely only on those I can purchase. I am rapidly coming to the conclusion that these particular bullets simply won't perform in my rifle....but I am at a loss as to what to try next. ANY help would be greatly appreciated. Thanks !

[NVcurmudgeon]

Three 98 Musers have given me great results with cast. The barrels ranged from barely discernable rifling in a 1933 k98k to an as new 1948 Yugo. Are you getting all the jacketed metal fouling out every time you clean? It makes a big difference. Are your boolits commercially cast? You might try Bulllshop, he knows his stuff.

[Freightman]

Most of the cast I purchased were to small, your best bet will be to order some from Bullshop. I would ask that they be .324/.325 for that bore.
I have a Turk that loves the 240g KBAR boolit but you have to size the nose .308 to get it to chamber which lets you out on that one. The LEE 175 g works fine also and you do not have to size the nose. I am fixing to get into trouble, but here goes the Unique loads are good, but I have a Hakim and they do not cycle it and I do not like a simi auto as a single shot so I push them harder with IMR 3031, 4898 ,414, 4198 ect no problem with leading crno above 1700fps. I have a couple of cases of surplus ammo that a I haven't opened since I started casting my own if that tells you anything. Chasing the brass from the Hakim is an experience in its self.
I also use cast in my M1 Garand and my SKS and AK and at speeds to cycle all.
I didn't want to cast my own but the commercial I bought gave me leading so for years I just used j word bullets. Got to expensive so I bought a mans whole set up and it is addicting to say the least.

[Three44s]

I would invest in a book from Beartooth Bullets on shooting cast bullets.


http://www.beartoothbullets.com/index.htm

On the left side bar ..... click on Shopping Cart

Next screen ....... click on book


Three 44s

[Larry Gibson]

Quite frankly while your barrel isn't perfect I've never met such a barrel that wouldn't shoot cast reasonably well. I see no reason yours shouldn't either. can you answer these questions for me?

What bullets (make, design) are you using?

Are they GC'd?

Do you know the alloy or the hardness?

Are you chronographing any of your loads or have any isea of what the velocity is?

Are you NS'g?

Is the base of the bullet seated below the case neck?

What powders and what is the range of the charges?

Larry Gibson

[bcp477]

Thanks for the replies (and suggestions), gentlemen. To answer one poster's question, yes the bore is as clean as I can make it, including metal fouling. It is clean enough so that I can, for example, swab the bore with Sweet's 7.62 or Hoppe's #9...wait 20 to 30 minutes....and get NO blue colour on the patches at all. Visually, with a borrowed borescope, the pits in the surface are clearly visible...and the bore surface appears quite clean.

As for your questions, Larry....I will try to provide the best info I can.

First, the bullets are .324" sized, flat-nose 170 grain, designed for the old 32-40 cartridge, originally. I purchased them from Hunter's Supply, if I remember correctly. I have no information as to the mold used for these. The bullets have 2 lube grooves and are pre-lubed with a smokeless-compatible lube. I have LIGHTLY coated them with Lee Liquid Alox before use.

Next....they are plain-based bullets, not gas-checked.

I do not know the alloy or hardness, other than to say that they are "supposed" to be 12 or above, on the hardness scale, according to the company literature I have.

I have not chrono'd any of my loads, but my estimates/ calculations indicate roughly 1000 fps on the low end....and roughly 1600 fps on the high end (no guarantees, of course, just the best estimate I can generate). Given that these are plain-base bullets, my original intention was to keep the velocity below 1400. The manufacturer says that the bullets are good for up to 1600, without leading problems. Thus far, I have had absolutely no leading at all...at least none that I can determine.

Excuse my ignorance, but what is "NS'g" ???

The bullet bases are not seated below the case necks. These are relatively short bullets and that would not be practicable with these, anyway. (I do realise that seating below the case necks would not be desirable.)

As for powders and charges....so far, I have tried 2400, from 12 to 17 grains (with dacron filler)....IMR-4895, from 18 to 23 grains (with dacron filler).... surplus pull-down Yugoslav military powder from 8mm ammo (which is a fairly fast flake powder), from 16 to 25 grains (with dacron filler)...and finally, Unique, from 8 to 17 grains...(both with AND without the dacron).

At this point, my thinking is that I should try other bullet styles/ weights, such as from the Lee 175 mold....and gas-checked ones at that. Also, a bit higher velocity (using gas-checked bullets) might be indicated. Also, perhaps I should try bullets sized no smaller than .325", if I can find any. I do not have a bullet sizer/ lubricator....and I would prefer not to have to get one. The odd thing is.... I have been in contact (on the net) with a number of others (using M48's, 24/47's or K98's), who have had no difficulty in getting good accuracy with 170 grain cast bullets, sized .324". So, I am at a loss as to why I am having such difficulties...especially since my barrel is so accurate with the jacketed loads I have developed for it.

Anyway, thanks again for any useful suggestions.

[Larry Gibson]

Thanks for the resposes to my questions. Sorry; NS'g is neck sizing. From the powders and charges listed my guess is you are driving them too fast by the time the powder is burning efficiently. Some plain based bullets just don't like to be driven fast, especially in rifle cartridges.

Try this with them; load 10 each of them over 5.5, 6 and 6.5 gr of Bullseye and test them at 50 yards. If they don't shoot with one (or all) of those three loads then the bullets are just not compatable with your rifle.

Larry Gibson

[bcp477]

"NS'g".....ah yes, NECKSIZING. Yes, after initial fireforming, I necksize only, most of the time.

Thanks, Larry. I'll take your advice....and give it a try.

[Bret4207]

In my Yugo I find the 8mm Karibiner, a GC design of some 230+ gr and 13.0 Red Dot to be a sub 2" load, assuming the nut behind the buttplate does his job. You'll find a GC makes life much easier.

http://www.midsouthshooterssupply.com/item.asp?sku=000068MMKAR

[TAWILDCATT]

I was going to sugest 13 gr red dot with the 170 gr.thats my load in 1903 spring.
I crony the load at 1680fps.---[smilie=1:----:Fire:----:coffee:

[bcp477]

OK, so I have had a chance (finally) to test the advice I have been given as regards these cast bullets, in my M48. Larry Gibson...you were exactly correct when you asserted that I was (previously) driving the bullets at too great a velocity. I tested these same bullets with MUCH lighter loads (namely 6.5, 7.0, 7.5, 8.0, 8.5 and 9.0 grains of Unique....with dacron filler added)....and got much better results. The 8.0 grain load was the most accurate of the lot, with group sizes (two groups of 5 shots each) of about 2" at 50 yards. So, these bullets appear to be usable in my rifle, after all. Eureka ! I have loaded the rest of them that I have on hand....at 7.8 to 8.2 grains....to refine the load. Since these bullets are easy and cheap to obtain, I shall probably try more of them.

Thanks to all for the good advice and encouragement.

[bcp477]

As a final note, I have found that 8.1 grains of Unique, plus a bit of dacron fibrefill, works best with these bullets, in my M48. This load does produce acceptable results - 2" or smaller groups, at 50 yards. I also got a chance to chronograph some loads today....and this load produces an avg. of 1145 fps, with a std. deviation of less than 15. A bit faster than I expected, but pretty consistent through my ragged old barrel.

So, overall, I am pleased. Again, a big thank you to all who offered advice. I think that I shall add this load to my list of "acceptable" loads...and order more of these bullets.

[Papa smurf]

bcp477-I have good luck with two loads in my yugo.
Lee boolet,alox lube,with gas check.
14.5 gr unique and 30.0 gr surplus 4895,both clock 1600fps.
The unique load is the more accurate,4895 leaves some unburnt powder.
I dont use fillers,never found a need for them.
Hope this helps you. Papa smurf

[wildwes]

I realize this is an old thread, and you probably have your loads worked out by now, but just for info, I load cast for my M48A, which slugs at .324 with very good results. I load the lee 175 grn boolit, gas checked and lubed with BAC lube, seated to the crimp groove, with 22 grns of IMR 4198 behind it. It isn't a barnburner for speed, I have to move my sights up, but it groups very well in both my M48A and my grandaddy's. If I do my part my rifle will shoot 2" at 50 yds with this load, and if I put it in a gunvise and fire it, totally eliminating my error, it'll do around 1" Like I said, it's not fast, but it's very accurate in what I've tried it it.