westerner wrote on Dec 31^st, 2016 at 8:38pm:

Did Chuck make a 250 with his Darr HiWall? With most 250s being shot with BR rather than traditional stocks, I have always felt that was the primary factor leading to the increase.

Am I correct in thinking nose slump is directly related to bullet hardness - all other factors being the same? Also, regarding hardness, there has to be a point of diminishing returns.

About 3 years ago I read John Lewis' theory of nose slump.  I had been shooting a Darr spritzer of 208.5 gr, 20"1, in a 16 twist barrel and always had noticeable tipping at the target, but pretty good grouping.  For Raton that year I added more tin to get about 17:1 alloy, and upped the charge of 4227 about .4 gr.  That match I shot my first (and only) clean target.  I think there's something to the slump theory.

Regards, Joe

Joe Barry Darr did exstensive catch box nose slump testing and shared his eye opening findings with me several years ago. If you found an improvement by changing the hardness of your bullets the credit needs to go to Barry. I have only shared what he has so kindly shared with me, took it to heart and then took the time to prove increasing the bullet hardness as being a big benefit in increased accuracy and consistency to myself.

JLouis

it would appear that 10:1 is as hard as you can go with just lead/tin.
any more tin is wasted.
have not read of the o.d.g. long range shooters going harder than 11:1.
with charges of up to 112 gns of black, they would well have understood nose slup and setback.
keep safe,
bruce.

Small changes in tenths of a grain in powder is typicaly more directly related to tempreture and altitude changes and would not typically be directly related to the improved accuracy found in the increased bullet hardness. The key word being typically and based on Joe's change in location and the altitude already being a known big change it could have simply just been a quite typically called for adjustment for his rifle to stay in tune.

JLouis

"Has anyone studied ...........same mould, brass, powder, charge, primer, seating depth, range conditions, etc. .............the only difference being the ratio of (certified) lead:tin?"

I think you lost track of the above original posted question and no I do not take chances when I pull the trigger and I hope this answers both of your questions.

JLouis

j louis,
yes i have, and that was among the tests.
other tests included compression, primers, and wads.
i booked the lower light fullbore range, and ran tests all day at 900 meters.
a good friend pulled the target, and photographed the groups.
being the only one shooting on a 1000 yd range is an almost eerie experience. shots seem to be much quieter than usual.
wind conditions were very similar all day (luckily.)
at those distances, vertical becomes a more meaningful measure than round groups.
from memory I was averaging about 15 points of wind.
started too close to the flagline . some sighters went through 2 flags, and had to move further out onto the range.
interestingly they still hit the target, but low.
keep safe,
bruce.