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Re: A cheap bullet pointing system

Posted: Mon Jan 22, 2018 10:43 am
by ColinR
Ovenpaa wrote:Colin, the 168 and 175 SMK's are quite blunt to start off with so are not ideal for pointing however if you would like to send me a couple of each I can check and see how well the point up.
Will do during next couple of days - many thanks

Re: A cheap bullet pointing system

Posted: Tue Jan 23, 2018 10:04 am
by EagerNoSkill
I have found that with pointing the overall group size off say 10 shots over 300 yards also reduced significantly.

What people fail to realise is that besides improving the BC by +- 4 to 6% (depending on the bullet) it also dramatically reduces the vriation in BC (reducing the extreme spread in BC.

This reduces the high and low shots due to BC variations.

AT 1000 yards the difference in elevation spread was 0.3 moa vs unpointed and pointed.

Re: A cheap bullet pointing system

Posted: Tue Jan 23, 2018 3:50 pm
by Hunter87
If you want pointy bullets on the cheap try this.

Re: A cheap bullet pointing system

Posted: Tue Jan 23, 2018 6:13 pm
by Laurie
EagerNoSkill wrote:What people fail to realise is that besides improving the BC by +- 4 to 6% (depending on the bullet) it also dramatically reduces the vriation in BC (reducing the extreme spread in BC.
Tim, if you get hold of a copy of Bryan Litz's Modern Advancements in Long Range Shooting Vol II, you'll see that the BC improvements were nowhere near 4 to 6%.

As the 175gn SMK .308 Has been mentioned, Bryan's tests which saw the meplat diameter reduced from 0.064" to 0.050" improved BC as measured over 300 yards from 0.243 to 0.244 G7.

Yes, I know that Dave's (Ovenpaa's) device likely reduces them more remembering your bullets which I looked at during an F-Class 'Europeans' some years ago, but Litz's tests of a large number of bullets in all main calibres shows very disappointing improvements, even if most are better than that 0.001 for the 175gn .308 SMK, but as Dave pointed out (Groan!!) a post or two back, it's not a great candidate for the process anyway. Taking the once popular 155gn Scenar which starts with a large (0.080") meplat reduced to 0.065", the average G7 BC changes from 0.224 to 0.229, only 2.2%. The SD of the range of BCs measured for pointed examples does improve, but mostly by small amounts.

Re: A cheap bullet pointing system

Posted: Tue Jan 23, 2018 8:14 pm
by EagerNoSkill
Yes he did report that...but it depends on bullet and the pointer.

With David's pointer I did following
Pointed 10 x 155 hybrids.. Left 10 Standard
Shot at 1000 yards one of each in sequence
I plotted fall of shot..
Got average POC for each group
Then enter the Berger BC.... And launch Velocity and Environmental
Then on pointed load adjusted BC till I got the net change in elevation.

Results 6% change

Another Shooting Shed client did his own test on 155 hybrid with similar results.

Re: A cheap bullet pointing system

Posted: Wed Jan 31, 2018 6:13 pm
by Berger
The shooting shed sell bullet pointing dies and parts to customise redding or Forster dies