MBC 205 hitec 8x57

[Ivan21]

I bought some 205 gr cast bullets for my mauser I tried finding data for it but was mostly unsuccessful. I decided to try bluedot since I use it for reduced jacketed loads. So far I tried up to 18 gr with a mag primer. Velocities are consistant but accuracy is terrible. I am getting no leading. I don't want to try pushing bluedot so stopped at 1735 fps. Tried 12 gr of unique and got keyholes. Would I be better to use rifle powder?

[runfiverun]

you should have had decent accuracy at the blue dot velocity's, maybe.. depending.

do these boolits use gas checks?
no?
there is your problem, back the unique down to about 8grs.

what is their diameter? .
323 that's too small unless your shooting a Remington 700.
and even then another .001 would help.

[Ivan21]

you should have had decent accuracy at the blue dot velocity's, maybe.. depending.

do these boolits use gas checks?
no?
there is your problem, back the unique down to about 8grs.

what is their diameter? .
323 that's too small unless your shooting a Remington 700.
and even then another .001 would help.

They are plain base, hitec coated at .324 with 20 bhn. If it is tumbling at 12 gr, won't 8 be even worse? I from reading I thought powder coating replaces gas checks. This is my first time shooting cast in a bottleneck so I with try the suggestion. I was hoping for 1600- 2000 fps but will be happy with anything if it's accurate.

[Scharfschuetze]

My luck with plain base bullets over 1,300 or so has not been very good in 30, 31 and 32 calibre military rifles.

As Run5Run suggests, set a velocity goal of about 1,200 fps and use Unique or Green Dot powder. I can help you (with a PM) with the proper charges if you don't have the Lyman Cast Bullet Handbook. You can work up from 1,200 until you start to loose accuracy.

If it is tumbling at 12 gr, won't 8 be even worse?

No, I don't think so. The Mauser's fast rifling twist (under 1 in 10" if I recall correctly) will handle your bullet at 1,200 without tumbling.

[Ivan21]

Thanks. I will back it down and try some more. I have an old rcbs cast reload manual and accidentally bought the wrong lyman one.

[Scharfschuetze]

Thanks. I will back it down and try some more. I have an old rcbs cast reload manual and accidentally bought the wrong lyman one.

Update:


I just checked my loading log for the 8mm and found the following:


165 grain plain base flat point sized .325 with ALOX lube.
8.5 grains of Bullseye powder
CCI 200 LR primers
Winchester cases, no crimp


Velocity: 1,285, Es: 102, Sd: 25


Rifle used was a BYF 43 Kar 98, an Oberndorf Mauser that apparently saw no action in WWII.


Not very uniform ballistically, but fairly accurate out to 200 yards. 3 MOA accuracy. No leading and no notes of bullet instability.


While this is with Bullseye powder and a lighter bullet, you should be able to duplicate its performance easily with the slower Unique, perhaps with better accuracy given your longer bearing surface of the heavier bullit.

[popper]

PB groove less bore rider? How does the nose fit?

[Ivan21]

PB groove less bore rider? How does the nose fit?

I believe it is. It is surprisingly short for being so heavy. I'm not sure what you mean by fit. It won't fit in the barrel without substantial force.

[runfiverun]

you want the nose to engrave, so that's good.

Hi-Tek isn't a powder coat, it is a cross linked polymer.
they are similar in some way's. [some P/C's are polymer based too]
but you have to think of hi-tek as more of a stain and PC as a paint.

[Ivan21]

Thanks for the info. I was almost ready to give up. I reset this morning and used the suggested charge of unique. This helped but wasn't perfect. I then tried seating to crimp groove and crimped just enough to stop bullet setback and shot 3 into what looks like 2 holes at 25yds. With that seating depth the bluedot was within an inch.

[runfiverun]

looks like you now have something to wok with.
bump the unique a bit here and there and move out to 50 yds.

[Ivan21]

50 yds gave a 2.26 10 shot group at 1179-1187 fps.

[Scharfschuetze]

Great! Now you have a base line to work with. Different powders and possibly lubes may very well tighten things up a bit.

With these light (squib) loads, you may find your cases' shrinking a bit from the head to their datum line. Nothing to be too concerned about as the big claw extractor of most Mausers will eventually hold the case against the firing pin's strike. If you want to get around that issue, there are threads on drilling out the flash hole to help equalize the pressure between the high pressure of the primer pocket and the low pressure within the case at these low velocities and pressures.

[runfiverun]

that works and just loading them with a low end jacketed load will puff the cases back up too.
I fire form all of my cases with jacketed loads so the brass is form fit to the chamber.
this gives me 5-7 firings of neck sizing before I need to anneal and blow them back out again.