Delving into a new area of PP!

[RMulhern]

Well....I've been curious as to how PP would work patching up to groove diameter as all my shooting of PP the last few years has been that of using bore diameter patched bullets. I've had good success with this method but today I loaded a couple of rounds to bore diameter to get the required dimensions down pat. Tomorrow I'll load up 25 or so and see how they shoot....provided the conditions of weather permit! These are for my C. Sharps 50 2 1/2 using a KAL 690 gr. Elliptical bullet. I've loaded 114 grs. Swiss 1F and using regular type bond paper for patching...the finished OD is at .512". The base of the bullet had to be put .517" below the mouth of the case so as to get the front of the patch just touching the lands. Using this method I'm worried that with the bullet so deeply into the case that there is more likely-hood that the base of the bullet will have more chance for over-expansion in comparison to the bore diameter which the bullet is more akin to having been breech-seated! One thing I do like however is the fact that I did not FL resize the BELL brass and the .512" patched bullet fits tightly into the case not requiring any taper crimp! Time will tell with shooting I guess!

[montana_charlie]

[RMulhern]

Yes sir Charlie....I'm reading ya mind! You're sittin up there thinking...."Well....I wonder if this Ole Boy is gonna prove MY WAY right?" Come on now...admit it!! Never let it be said I'm set in my ways because I'm really gonna give this a serious try......regardless of the fact that I HOPE I'M WRONG! What I really believe is that this groove diameter is going to give me some SERIOUS MISERY with poor accuracy in addition to making me MINE LEAD out of this 50 bore!! With this being said....if this rifle had a true PP chamber it might be OK but a standard chamber with that 45* angle???.....just don't think it's going to deliver what's needed but I will certainly show the results thereof when I get a chance to try these rounds I've made!

[montana_charlie]

Yeah, I admit that you're right. I am hoping you will validate my experiences.
I am extremely glad that somebody who knows how to patch a bullet...and who has already succeeded with the bore diameter 'fudge'...is going to give patched to groove a fair trial in a BPCR application.

Mine has the 45 degree step and I did get a paper ring when I shot a short case...only happened once.
CM

[45 2.1]

Not trying to intrude, but just what are these factors:

1. Throat diameter
2. Bore diameter
3. Groove diameter
4. Prepatched size of your slug

Some things between your BP patching method your used to and what your trying just aren't the same. BTW, are you going to wipe also?

[montana_charlie]

Using this method I'm worried that with the bullet so deeply into the case that there is more likely-hood that the base of the bullet will have more chance for over-expansion in comparison to the bore diameter which the bullet is more akin to having been breech-seated!

The base of a patched to bore bullet is able to expand because it is only bore diameter...and the case had to be sized down to hold it. That means the case has room to expand in the chamber, and will let the bullet do the same. That's why they seat patched to bore as shallow as possible...so less of the bullet gets 'damaged' by over-expansion.

With your patched to groove bullet seated snugly in a fireformed neck, it can't bump up any bigger than it is right now.
Since it already matches the largest dimension in your entire barrel, the only change (when it exits the muzzle) is that the rifling will have 'engraved' the bullet...unlike patched to bore, where the bullet has to 'expand' to fill (or partially fill) the grooves.

CM

[montana_charlie]

Not trying to intrude, but just what are these factors:

1. Throat diameter
2. Bore diameter
3. Groove diameter
4. Prepatched size of your slug

Just to keep some chatter going, I will guess that Rick's answers will be pretty close to...

Throat / Groove .512"
Bore .500"
Naked bullet diameter .504"

Now, we can wait to see if Rick confirms any of that..

CM

[RMulhern]

Just to keep some chatter going, I will guess that Rick's answers will be pretty close to...

Throat / Groove .512"
Bore .500"
Naked bullet diameter .504"

Now, we can wait to see if Rick confirms any of that..

CM

CM

Yep! That's it! Except the naked slug OD=.494".

[45 2.1]

CM

Yep! That's it! Except the naked slug OD=.494".

You will probably not get good results (worse than than your normal way) with that. The slug would need to be very close to bore diameter, or slightly over, for what your trying to get better results. What your trying has been experimented with extensively by several people with BP, just not anyone of your crowd.

[montana_charlie]

Hmmm...
Rick, I'm surprised you picked such a small bullet. I guess that you are (now) stuck with using those thick papers...instead of the good old onionskins that you are familiar with.
CM

[Lead pot]

I use a .498 naked for the .50.
I talked to a few guys that use the small diameter bullet and use the printer paper and I guess they are doing good doing it this way.
I did it in the .45 using a .433 with the printer paper and did not get along with it.