[Marshall Stanton]

Brian,,

Your load will be turning about 1000 fps if I'm not mistaken, and it might well be that 1.7" 25yd groups are all you're going to get from that bullet.  Generally with a .45-250g bullet, 10.0g Universal Clays is an accurate load.

Can't say for sure, just a hunch.  It's kind of like giving a haircut over the phone!  I don't know if the bullets are PB, BB, or GC, how hard they are and what the ogive and bearing band configurations are like.   Mid-Kansas makes machine cast bullets, and there are included air-voids in many of those bullets that will introduce uncontrollable variables that you might not easily overcome.   One of the reasons for our strictly hand-cast operation... consistentcy!

Probably not the answer you were looking for Brian.  

Have a safe and Blessed New Year!

Marshall

 

[Marshall Stanton]

Brian,

I suspect that your loads will open up more with the 10.5g and 11.0g loads of Universal Clays and your .45-250g Bullet rather than close them up!  Perhaps the lighter loads will shoot better, but only testing will show for sure.

Let us know what you find!

God Bless,

Marshall

 

[Marshall Stanton]

Brian,

I've said before that as you mentioned in your last post, bullets with a longer bearing surface will generally be more accuracy prone than those with shorter bearing surfaces.

Also, machine cast bullets are very prone to have air inclusions in the bullet, making them unbalanced to a degree, thus hampering fine accuracy.  This is not always the case, but can and does happen.

Now, about the BHN and PSI obturation issue.  Yes the figures you have quoted are right as rain.  And, with bullets that don't properly fit cylinder throats because they aren't sized properly and obturation is necessary for the bullet to seal off powder gasses and prevent blowby and gas-cutting, this can be a real issue.  However, it sounds as though your bullets are well mated to your cyinder throats, and obturation isn't an issue here!

We can all get caught running down blind rabbit trails, and spend lots of energy and time going nowhere.   I suspect that in your case Brian, with your custom fit throats on the Ruger Bisley, that obturation for accuracy is one of those rabbit trails!  The bullet fits from the sounds of things therefore there shouldn't be any gas cutting or blowby.  Obturation shouldn't be an issue.

I shoot volumes of our BHN 21 bullets at 700-900 fps with perfect accuracy, and I know that they don't obturate with the loads I'm using!  Keep in mind all RNFP profiles aren't created equal, and some don't have a strong front driving band.   This difference in designs can make a huge difference in accuracy potential.  If you will note the bullets we carry all have very strong front driving bands.  There is a reason that we don't make and sell some of the more common bullet designs... they aren't all created equal!

You might try different powders, or perhaps a different crimp.  Both can make big differences as can primer selection when it comes to accuracy in these relatively low pressure, low velocity loads.  But to chase after different hardness bullets, when what you have fit the cylinder throats so well, I beleive is one of the proverbial rabbit trails.

Yes, I know there are varying schools of thought, and one isn't the definitive answer over the other... I'm just sharing my experiences, such as they are and my very biased opinion.

Don't know whether it helps or not, but have a great day!

God Bless,

Marshall

 

[Marshall Stanton]

Brian,

If you're into playing with variables in your light loads, try moderating that crimp!

A couple of things come to mind here.  First, you are using the Redding profile crimp die which puts a firm and solid grip on the bullet, but perhaps too firm in this case.

It could be that with the Mid-Kansas bullets you are using in BHN16, that the severity of the Redding profile crimp die might be crushing the bullet undersize!  It is possible!

If you're curious, use an inertia bullet puller, and use your micrometer on the pulled bullet... it might indeed now be undersize!

With our BHN 21 bullets that won't be an issue, but with softer bullets I've seen it happen.   I'm not saying that it has, but I'm still trying to give that proverbial "haircut over the phone"!

Sometimes just a change in crimp itself can change the behavior of a load.   Try using just a light roll crimp.   It will be enough to hold the bullet with these light loads you are using, and see what happens.

I'm running out of ideas for you, but please let us all know what you find with the crimp situation.

These bullets that are giving problems... have you weighed them for weight consistantcy?  It might be revealing to do so.

See what happens!

Blessings to you my friend!

Marshall