The 7mm Lee Soupcan???

[leadhead]

I have several 7mm mausers that I've shot over the years with various heavy 7mm cast bullets.
I was always under the impression that the 7mm mauser was rifled for a heavy 175 grain bullet.
I have been playing with the Lee soup can at about 140 gr and have found they shoot very well.
In fact, they shoot better than any other bullet I've tried. Is it a case of the lighter charges of
powder, velocity, or something else? I'm at a loss for the answer. Anyone have any ideas?
Thanks for any info....
Denny

[UBER7MM]

Denny,

The original 7x57 Mauser rifles fired a 173 grain round nose jacketed bullet from a 1:866" twist barrel, at 2,300 fps. As owners will tell you, most of these older foreign guns slug at something over the .284". Current US made 7mm barrels are 1:9" to 1:9.5", and even 1:10" that slug at .284".
.
One theory to consider is the amount of boolit contact with respect to rifling groove and land width. Thick rifling types (small cut grooves and mostly heavy lands) tend to like a bore rider design better. While the thinner rifling (more groove area) would like a full dimension design with a shorter nose: (By your description, the 7mm Soup Can fits this theory.)
http://castboolits.gunloads.com/showthread.php?156297-Bore-riding-bullet-questions
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RPM theory:
You might like to look up boolit RPM and velocity. This theory seems to explain the slow twist barrels designed for lead projectiles. Also, theory projects that too much or not enough velocity changes the RPM sweet spot range and degrades accuracy:
http://castboolits.gunloads.com/showthread.php?208186-RPM-Threshold-barrel-twist-velocity-chart
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Greenhill:
The Greenhill formula, is a 19th Century artillery shell equation. Simply put, it explains the relationship of a projectile length and rifle twist for a given velocity or velocity range. The shape of the shell was also a formula back then and pretty much a constant. IMHO, this theory fits the model of why some longer jacketed bullets don't group well, while shorter ones do for a particular twist. Or comparing two different rifle twists of the same bore diameter for a particular bullet. (All other things being the same, which they aren't!):
http://castboolits.gunloads.com/archive/index.php/t-4945.html
.
It could get expensive finding the right boolit to group in one's rifle. Glad to hear that you've found one that works.
.
I hope this helps,

[MarkP]

They shoot well in my Remington Rolling Block in 7 x 57; never tried any heavier cast.

[TCLouis]

I have been using it in a Husky 7mm Mag with great results.

[leadhead]

Thanks for the info guys, I have several other 7mm's I'm going to try them in.
Denny

[sgraham3]

I was told the heaver bullets usually shot better but I really like the looks of this bullet so I just ordered one of these molds. Can I ask what powders your using?

[brstevns]

Can you tell us your load? I too have a old Rem. Rolling Block in 7x57
They shoot well in my Remington Rolling Block in 7 x 57; never tried any heavier cast.

[leadhead]

I'm shooting between 16 and 16.5 grs of 2400. I shoot this load in all my
military rifles.... Never found anything better.
Denny

[brstevns]

Would you feel safe using this load on small whitetail out to 75 yards?


I'm shooting between 16 and 16.5 grs of 2400. I shoot this load in all my
military rifles.... Never found anything better.
Denny

[Larry Gibson]

I've found milsurp barrels of M93, M95 and M98 actions to vary in groove diameter from .286 upwards of .291 with corresponding variation in the bore diameter. Most of the better M95s and M98s run in the .287 - .289 range. I've found over the years that bullets with longer bearing surfaces (both cast and jacketed) and flat bases generally shoot the best in these milsurp barrels. In my M95 7x57 with a pristine barrel (.288 groove diameter) I've found the older Loverin style RCBS 28-168-FN to be an excellent cast bullet as it drops at .287 - .288. The older Loverin 287405s if they drop at .288+ also do very well in the older milsurp 7x57s.

Larry Gibson

110439

[leadhead]

Yes I would but I don't hunt anymore. It's accurate enough to pretty much
center a 10" steel plate at 200 yds. off the bench.
Denny

[TCLouis]

brstevns

Look for Junior1942's discussion of this boolit and 7mm TCU.

Should be about the same velocity range in the RRB.