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BHN for rifle bullets

Posted: 15 Jul 2014 09:53
by beekeeper
I'm sure it has been asked before but I couldn't find it.
Trying to improve my groups and am grasping at straws.
What do you think the ideal BHN should be for a 308 ,7MM,8MM bullet?


beekeeper

Re: BHN for rifle bullets

Posted: 15 Jul 2014 11:16
by Ranch Dog
beekeeper wrote:I'm sure it has been asked before but I couldn't find it.
Trying to improve my groups and am grasping at straws.
What do you think the ideal BHN should be for a 308 ,7MM,8MM bullet?
I use a Lyman #2 clone alloy of my mix, 19 BHN, water quenched at the drop in calibers from .22 through .48. I believe it is a number for factors coming together to also include bullet fit and bullet design.

Re: BHN for rifle bullets

Posted: 15 Jul 2014 16:26
by 62chevy
I read once fit is king and hardness matters when it matters.

I guess the next question should be how fast are you going to shoot them.

Re: BHN for rifle bullets

Posted: 16 Jul 2014 07:39
by beekeeper
I try to stay in the 1800-1900 range. Am not always successful especially if I am playing with the surplus powders.

The bullets I tested with the lee hardness tester yesterday are in the 15-16 BHN range.
They shoot reasonably well but I still get a lot of fliers ( which makes me mad and then it gets worse)
Frustration sets in and I lose my concentration which makes it even worse.

So I am back at the beginning and starting out with the basics.
Brass weight and mfg code and date.
Weighing each load.
Now the bullet weight and BHN.

I'll get it someday but that is what makes the search worthwhile.

You have to understand I was doing this alone for years before I even owned a computer and found loading websites so being able to interact with someone else that shoots cast is a great boon.


beekeeper

Re: BHN for rifle bullets

Posted: 16 Jul 2014 12:00
by RBHarter
What I find really irritating in shooting cast Is that you'll get 1 that just works right outta the gate and 1 or2 more that just take a little tweek and then you get 1 that everybody says '' oh yea mine shoots dime groups '' w/this or that load thats exactly what 10 others shoot in theirs and yours shoots 12'' 25 yd groups....... on the good days.

I have a trio of 7mms from a 6.8Rem up to 280AI via 7x57. Everybody swears by those Loverin boolits.....I shot them fast,slow,checked,unchecked,Unique ,Red Dot,10x,IMR4350,both4831s....key holes,1 target actually showed the ridges. The 7x6.8 shoots 27-130s paper patched at 2230 fps and consistantly covers 5 w/a quarter @ 100. the 7x57 is getting close w/a 7mm-168 (1908 Ovieda built around a 175 gr rn fmj w/100 yr of questionable care found in a bbl of scrape metal). I think the only hope for the AI, which isn't actually an AI but a very similar wildcat,will be to set the bbl back and recut the ''real'' AI.

Re: BHN for rifle bullets

Posted: 05 Sep 2014 00:18
by dromia
Bullet fit is the key.

For velocities up to 1800 fps I like a relatively soft alloy. My "standard" is range scrap, because I have and can get plenty of that, mixed with pure lead to give a BHN of around 11-12. This has never failed me in smokeless rifle loads up to 1800 fps and in most cases loads up to 2000 fps.

For faster it isn't so much a case of a hard alloy more a tough malleable alloy, for instance lino type is hard and brittle and I don't get good results with it very often.

I'm no metallurgist but the current thinking over on CB, and my own modest observations concur with it so far, is for most alloys the best situation is to get the the tin and antimony quantities the same as this gives a balanced alloys.

For higher velocities then the addition of just less than 1% copper is the trick that works for me, this gives me a nice tough alloy of around 18-20 BHN and this is what I used to use for my 1000 yrd 303 competition shooting. With this alloy and loads I could hold and better my averages with cast over jacketed.

Get your bullet to fit the throat of your rifle along with a good lube and good bullet QC, I batch weigh all my rifle bullets for anything over 200yrds, along with good handloading practices like consistent bullet retention that doesn't size the bullet down or deform it when seating and concentricly seated bullets to ensure that the bullet isn't damaged during the jump into the rifling will give you good results.

Driving lead fast is achievable but it does take attention to detail at all of the reloading steps along with understanding the nature and properties of cast, loading cast with a jacketed bullet mindset will rarely give decent results.

Re: BHN for rifle bullets

Posted: 23 Sep 2014 12:36
by Maximumbob54
Check your bullets for still being as close to round as you can get. I've found many in the past where the sizer swaged them but the point was off to the left. I think when I drop them or maybe they stick in the mold a little they are ruined opening the mold too hot. I just know I've found some that at a glance looked fine but were not.