Thoughts on hollowpointing this mold

[shamu25]

Getting ready for deer season and wondering your thoughts on hollowpointing this mold.  It is a RCBS .41-210-SW and drops 220 grains with soft lead.  Shooting it out of my Extreme 40 cal at 3800 psi fill getting 3 shots at 848, 852 and 826 fps with Century 72056 S spring. Very accurate as you can see.  It has a wide meplat already but wondering its kill effectiveness at this velocity  if hollowpointed.   Also any guess as to what changes in accuracy I could expect.  The group shown is 5 shots at 40 yards.   Thanks for any input
Ray

[Allen A]

That's mighty good shooting Ray...350 ft/lbs of energy...I don't have a clue about hollow pointing the bullet though...

[FredSG]

Allen A.,

How do you arrive at "350 ft/lbs of energy" with the info Ray has posted?  Just curious as to the formula you used?

FredSG

[Mod90]

Looks like it'll take a deep & wide hp cavity really well. What's the OAL?

[Mod90]

An average velocity of 842 fps with a 220 grain bullet calculates to roughly 346 fpe atm. His calculations aren't that far off, more than likely he rounded up

Edit:
Kind of a dirty formula, but here goes

weight x speed x speed
              450240

[Allen A]

Allen A.,

How do you arrive at "350 ft/lbs of energy" with the info Ray has posted?  Just curious as to the formula you used?
Hi Fred, I used the energy calculator on AOA website...Al.

FredSG

[C.ALLS]

Getting ready for deer season and wondering your thoughts on hollowpointing this mold.  It is a RCBS .41-210-SW and drops 220 grains with soft lead.  Shooting it out of my Extreme 40 cal at 3800 psi fill getting 3 shots at 848, 852 and 826 fps with Century 72056 S spring. Very accurate as you can see.  It has a wide meplat already but wondering its kill effectiveness at this velocity  if hollowpointed.   Also any guess as to what changes in accuracy I could expect.  The group shown is 5 shots at 40 yards.   Thanks for any input
Ray

Good job on the tune! Brent's guns can be very efficient.

[shamu25]

Fred,
There is a calculator on American Airguns site which is simple and handy when you put it on your phone
http://www.airguns.net/calculators.php
Blessing
Ray

[PakProtector]

An average velocity of 842 fps with a 220 grain bullet calculates to roughly 346 fpe atm. His calculations aren't that far off, more than likely he rounded up

Edit:
Kind of a dirty formula, but here goes

weight x speed x speed
              450240

1/2-m-vee-squared...

450240 accounts for the conversion of grains to pound mass. 7000 grains/pound, 32.2 ft/second squared and of course 1/2...
cheers,
Douglas

[Mod90]

Well I did say it was a dirty formula Doug.

[KnifeMaker]

That may very well be a little too low in fps for reliable expansion. I would give Eric at Hollow Point Mold service a call, or e-mail him. He's the Guru for such things.

One thing for sure, it will have to be pure lead, with no more than 2% tin added for fill-out. Or it will be too hard to expand at such low fps.

Knife

[Mod90]

keep in mind that making that bullet with a HP cavity will lighten it up, which will increase its velocity. but that'd depend on the depth of the cavity. the thickness of the sidewall will have an impact on its expansion capabilities as well.
all in all we must remember that though expansion creates a nice wound channel, its penetrationot into the vitals and massive blood loss that puts game down.

knowing the goal will help with ideas on how deep and by extension how much lighter the bullet can be made.