K98 8x57 Mauser

[Spencer54]

Wondering if you can give me steer on where I go from here.

I'm shooting a K98 and using Lovex SO62 - according to Lovex I should be seeing 2500 fps.
According to my Magnetospeed I'm at 2300, using the exact bullets they list S&B No. 2910 @ 196 gr.

https://explosia.cz/app/uploads/2016/11/reloading_Lovex_EN.pdf

After firing my home loads next to PPU Match 8x57 they feel down on power in comparison, they certainly shoot lower.

According to the books I'm at max, but it sure doesn't feel like it.
From here am I better off looking at a crimp, or reduction in COAL - or just keep on going up in increments?

 

Thanks in advance

 

[Andrew]

Reloading data from manufacturers is only a guide, not an absolute. Usually, it is what they got on a given day using their equipment, LOT # of components, and assembled on their equipment. Crimping is always a good thing (to me) but chasing data numbers can be a losing proposition. They could be using a 600mm test barrel with an exact .323" groove diameter CIP spec chamber. Your K98 could be .326" with a military chamber. Do what you think is safe after you verify the speed with another chrono.~Andrew

[Spencer54]

Thanks I'll step up the powder and see how it goes, I'll get some factory 8mm and chrono that as well - that way I'll have some reference.

[Andrew]

In the US, 8x57 factory ammo is highly anemic due to the one time prevalence of Model 1888 Commission Mausers . This left me with nothing to go by when running sporting weight heavies in my 8mms.  My deer load for my 648 Husqvarna is a 208 grain cast bullet at just under 2400 fps. Accurate and lethal.~Andrew

[Spencer54]

PPU match leaves nice bruises on me - so I know thats the ballpark.

[Laurie]

QuickLOAD also says 2,500 fps or thereabouts for 47.8gn SO62 under this bullet in a 23.5 inch barrel (actually 2,540 fps from 49,728 psi, right where you want to be).

However ........... I was dipping into the 1,000 plus page compilation of the late Ken Waters' Handloader magazine articles over some 30 or so years of his handloading tests and lit upon his 8mm Mauser IS article originally published way back in November 1975 and mostly using the then Dupont IMR powders including 4064. (SO62 used to be called AAC-4064 in its old Accurate Arms persona and was sold as an alternative to the venerable US manufactured product. QL confirms this with 47.8gn of IMR-4064 computed to produce 2,549 fps / 50,950 psi PMax.)

Now, Ken Waters found using two different K98s (1933 DWM and Czech VZ-24) back in 1975 that his actual results were WAY down on what loading manuals prediced from their maximum loads - as much as 200 fps with 150 grainers for instance. On the other hand RWS sporting ammo chronographed very close to what the manufacturer claimed - and at much higher MVs than his handloads produced. Waters was so concerned by this he paid for the H.P. White laboratory to independently chronograph the RWS ammo and some of his handloads and they confirmed his findings.

He worked loads up to higher levels than in any of the manuals to reach the expected MVs (and what the German commercial stuff gave) and with the US IMR version of the powder got up to 50.0gn 4064 with the 196gn Norma RNSP for 2,539 fps MV. Waters did warn this was absolute maximum based on measuring case expansion! (QL predicts an over-CIP max pressure result from both SO62 and IMR-4064 for this with the 196gn S&B. For SO62, it says 2,654 fps and 58,065 psi)

There is then an addendum to the Handloader article saying Dupont had got in touch after it was published advising some of his loads were over-pressure in their pressure test barrel, so he warned readers about being very careful in using his data. But he couldn't explain the dicrepancies between the loading manuals / Dupont loads / MVs and his findings, finally putting it down to maybe throat wear on 40 year old used military rifles.

I suspect it is more to do with how barrels were throated. The Germans developed the 7.92X57mm IS heavy bullet loading during WW1 as an MG cartridge, but it was marginally unsafe in rifles. When the WW1 era rifles/carbines were redesigned into the KAR98k in the late twenties/early 30s a decision was made to use the 198gn sS (Schwerer Spitzgeschoss) MG round as the universal German military loading and the rifle chamber was redesigned with a long tapering throat to reduce pressures - 1 3/8 inches according to Waters. (Wow! That IS a 'freebored' chamber!) Those countries / factories that produced K98 type clones were also designed around the sS round and presumably copied the German chamber.

I suspect the powder manufacturers' test barrels do not have anything like this degree of freebore. QuickLOAD's equations  rely too on the bullet being at the rifling at whatever COAL is input and its results overstate pressures and velocities for those that have been 'freebored'. (To use a now out of fashion term in its original sense of having a massive designed inbuilt jump to the rifling. It was also an integral part of Ken Weatherby's 'magic' to achieve his cartridges' claimed MVs within high but acceptable pressures. My first ever loading guide was ICI Nobel's little paperback and I remember wondering what this 'feebored chamber' was in relation to one of the Weatherby cartridges. Nobel warned the data was only applicable to 'freebored rifles' and had to be significantly reduced for those with 'normal' chambers.)

So, all this leaves you just where? Where you are is that you need to beg borrow or steal a chronograph and see what you are actually producing in your barrel / chamber. If, like Ken Waters' findings, you're a couple of hundred fps down on what the loading guide says, you can carefully work loads up a bit using a chronograph throughout the process.  Without such data, you have to stick to Explosia's maximum for safety.

[Spencer54]

Thanks Laurie,

A trip to Bisley with the Magnetospeed produced some interesting results. I dropped the COAL length to 79mm as specced on Lovex's website. I started out at 47 as I had previously, then 48, then 49. My top measured result on the day with 49.0gr of Lovex SO62 was 2430 fps. I feel its still under what PPU match provides as they really let you know you've pulled the trigger. I need to chrono them next.

My guess that to get the 2500+ listed will require roughly 51gr which seems to tally with the Youtube video of a match 8x57 by PPU that was pulled apart and measured (51.7?).

My K98 is a Yugo rebuild with a new barrel by the look of it and at 47.5 gr was really printing tidy groups @ 100y.
I want to scope this eventually, and run it out to decent ranges, so I could do with a FPS that'll reach out.
I have noticed though that the sights are now shooting at the claimed ranges, not the 100yds over I was using since the 198 has been making 2400+.

 

 

[MikeJ]

I was always fairly surprised at the MV I used to get from my 1942 K98 (which had a far from perfect barrel). Using 46g N140 and the PPU 198g FMJ set into the case to the cannelure it was always around 2280fps. Even so, at longer distances (e.g. at Orion out to 800yards) the iron sights seemed to be fairly well calibrated. I never bought any PPU Match so am unable to make any comparison. I can't imagine how it would have felt if it had been stoked up any further! Your 2300fps might actually be perfectly reasonable, given all the variables mentioned by others on this topic.

 

[Laurie]

58 minutes ago, MikeJ said:

I can't imagine how it would have felt if it had been stoked up any further! Your 2300fps might actually be perfectly reasonable, given all the variables mentioned by others on this topic.

  Yes, on my second (of three) 7.92X57 - many, many years ago - I set out to finally have a centrefire rifle I didn't handload for and opted to shoot PPU FMJ ammo from it. (This was the old Berdan primed military spec sS PPU whose Cyrillic lettering on the case-head appeared to print 'nny'. It was excellent ammunition and cost £10 / 100, which was very good value even after knocking inflation effects off.) That determination to avoid handloading lasted for one very hot summer outing afternoon session only, its first, in no-jacket / sweater conditions and a four-inch diameter collection of bruises on the shoulder. IIRC the rifle was one of the DWM Portuguese Mauser-Vergueiro rifles that started as 6.5X58P but were shortened and rebored / rechambered to 7.92 in the 30/40s - a very nice piece that recoil aside I really enjoyed shooting.

Plan B was to pull the bullets on the PPU ammo and reduce the charge by 10-15%. This didn't work and it was found that anything greater than 5% reduction gave dismal (and dirty) results from the very coarse square-flake propellant. 5% off still kicked like the proverbial mule!

So ........... Plan C saw dies, bullets, and boxer brass bought and a mild and reasonably accurate 130gn Hornady PSP / Viht N140 handload adopted, the remaining milspec rounds given away to one of the many 7.92 IS shooting masochists in the club.

 

[MikeJ]

Ah yes...… I did have some of that 'nny' head-stamped stuff. It came in small cardboard boxes of, I recall, 25 rounds, in clips of 5. I recall that it was dated 1953 😨😨😨 but I never did take the opportunity to chrono it. I was more concerned with "enjoying" the shooting!

[Laurie]

That (cheap surplus) was an important attraction of 7.92 rifles of that time, the rifles themselves as WW1 and 2 German and east European / Persian / Turkish etc Mauser designs aside. I bought a few hundred surplus Portuguese rounds in Annan when on holiday in Dumfries & Galloway back in the late 80s. Again, £10 or some such low price per 100.

I always remember the gunshop proprietor saying words to the effect of: 'You know, only a few years ago, we had an offer where if you bought 200 rounds of this ammo we gave you a K98 free.' I was astonished at this amazing generosity and said so. 'Not really' came the reply  'We didn't promise any rifling would be included in the deal.'

(Companies like Parker-Hale had bought thousands of similar shot-out Mausers a few years previously and paid a few shillings each for them, solely for the actions as the basis of new builds, and no doubt a few other parts had some value. Numrich Gun Parts in the US built its business up too on the basis of buying and breaking vast numbers of these scrappers from the literally millions of surplus bolt-action military rifles that went onto the international arms market in the sixtiest to eighties.)

[Spencer54]

Just for completeness should anyone read this at a later date I managed to get some more time with the K98 and the chrono.

I did three sets of 50.0gr SO62, one with no crimp, one with a mild crimp and one with a heavier crimp.

Results were 2500fps, 2515fps, and 2570fps - the mild crimp gave a really low deviation so that's where i'm going to call it a day.
Happy with the results and accuracy - so thanks for all the pointers!