estimated MV ?

[jayd4wg]

lacking access to a chrony right now, i'm wondering if the load my rifle seems to like right now is sufficient.

I recently switched to 165gr SGK SP's in my .308 using CCI primers, winny brass, set to 2.800" OAL with 42.0 gr RL 15 under it. Each round is FL sized and run thru a modest press on the LFCD to seal them up for hunting use. I know i don't NEED to do this, i just do.

the groups are fantastic - roughly .2" at 50 yards, and under .5" at 100. I lack the resources at this time to shoot further but do not doubt that this round will stay stable to 300 which is realistically as far as I'll be shooting any time soon at deer.

using the Lee hardcover, i'm estimating MV of about 2550 fps. I know POI out to 100 is inconclusive to accurately estimate MV using POI method so i was wondering if anyone may have any insight as to whether this round, though slightly underpowered, should be sufficient with these bullets. I'm feeling stupidererer for even asking this here...but i'm putting on my thick skin ahead of time

just the usual dose of over analyzing without the right tools to check things the RIGHT way. I highly doubt this round is under any kind of lethal velocity range and I am fairly confident that the bullet will perform at this velocity just fine.

Rifle specs - 22" 6 groove, 1:12" twist and i'll have to remeasure the groove dia - but .312 is sticking out in my head for some reason

 

[jayd4wg]

Re: estimated MV ?

suppose that I should add...

I was working higher, and groups were beginning to shrink again around 46 gr's but i have stiff bolt and flattening primers at 46.2

I also have some varget to work with too, not much, but saving that for another known good load - cash is tight right now, waiting on a new job to come in that will increase the comfort level a little. I have a bunch of RL15 left, so i'm pretty determined to use it for this bullet (i have a bunch of the SGK165's now too)...

 

[Wes3377]

Re: estimated MV ?

I kill 20-30 deer a year on a high fenced game ranch and use them to test bullet and load performance. I've found that bullet placement is a lot more important than any other factor.

Anyway, one year I killed 15 or so does and cull bucks with a 165 Gameking at distances out to 550. I don't remember my load data, but my velocity at 550, I'm sure, was less than you are at 300. I did not have any problems with the bullet failing to expand. You will probably see deeper penetration with the lower velocity, since the bullet is not upsetting so violently on impact. Good hunting!

 

[Clark]

Re: estimated MV ?

I only kill 3 or 4 deer a year. The deer at 500 yards either drop dead, run 50 feet, or stagger 50 feet. They are getting hit with a 130 gr ballistic tip with terminal velocity of 1000 foot pounds and 1855 fps. The liver or shoulder hits are bang flop. The heart shots are run 50 feet. The lung shots are stagger 50 feet.
I shoot from a bench at a 100 yard range here in the Seattle area.
Then I drive 1000 miles to hunt.
Before hunting starts, I put a card board box on a hill, and shoot at from prone with a bipod.
I make corrections to the range vs drop chart that is strapped to my range finder.
I keep backing up. When I get to the range that I can't keep 3 of 3 holes within 6" of the bullseye, I am out of range.
That threshold is usually at 500 yards.
I keep hoping that if I read SH every day, someday that the limit of my range will grow to 625 yards.

What does it all mean?
The chronograph was part of my initial drop chart, but the corrected chart I hunt with is based on long range experience.

 

[jayd4wg]

Re: estimated MV ?

i do not disagree that placement is key. I've dropped them with 22WMR to the head before too. I guess i just get too caught up in the numbers and was concerned that the velocity would be too low...in the grand scheme of things, knowing what was posted above, my MV is going to be higher than you are getting out at 500 or so with the 165 SGK's and little thought to failure. I know the deer won't miss the 250 fps i'm missing...okay, thanks, and back to hunting LOL

as an aside though, is there a ballistics program that will (fairly) accurately estimate MV? seems rudimentary to a point, but then again there's alot of variables too. how much slop is in the barrel and the depth of the grooves in the barrel could eat up alot of the powder force. I'm thinking my groove depth is a bit off...6 thou' seems a bit much (again, lacking the full experience and time behind the butt to really have a good grasp on things overall...)

All i know is my freezer is now empty, and i cooked the last jar of canned meat yesterday. I have one pack of tips thawing right now that will be used in stirfry tonight and i'm officially sans bambi until saturday when i have the opportunity to burn a doe tag in the early archery season. the bow is a totally different story...a 20 year old bear whitetail II with truglow 3 dot, NAP EasyTune100 rest, custom string and cable, running cheap gold tip devastators at 29", with 100gr 4blade muzzy's. paper tuned last nite with the new arrows (never used carbon before) and i have nice little stars on the paper at 10 and 20 yards...they are flying true and fast at 230 fps out of that old girl...she's heavy but still works. hard to part with her.