Titan ReloadingRotoMetals2Lee PrecisionRepackbox
Reloading EverythingMidSouth Shooters SupplyWidenersInline Fabrication
Load Data
Results 1 to 17 of 17

Thread: A BC for an LBT??

  1. #1
    Boolit Buddy
    Join Date
    Apr 2015
    Posts
    156

    A BC for an LBT??

    I know this is an off the wall question, but if it can be answered, this is the place. 😀

    I have a. 430 mold from LBT for a Wide Long Flat Nose (WLFN) bullet that I acquired in the mid '90's. It drops at 320 grains with WW. I'm trying to do some calculations for a load in a newly acquired CVA scout rifle and need a BC to do the calculations. If anyone can help with this I'd be very appreciative.

  2. #2
    Boolit Master



    Join Date
    Oct 2008
    Location
    1720 miles East of Wall Drug, North of Cooperstown, NY
    Posts
    1,082
    If you have a chronograph you can record MV then move your crony to the 100 yard point by a target and get your true BC for the velocity you are shooting. There are readily available calculators for this.
    ΜΟΛΩΝ ΛΑΒΕ
    Je suis Charlie
    Remember Lavoy!
    I'll cling to my God and my guns, and you can keep the "Change".

  3. #3
    Boolit Buddy memtb's Avatar
    Join Date
    Sep 2016
    Location
    Winchester,Wy.
    Posts
    495
    I was curious about the same thing with some of my cast bullets. As a general statement .....for typical handgun ranges, the BC is relatively unimportant! All that said.....I did a little research and just called mine a 0.200 BC, assuming that it was “close enough for government work”! memtb
    You should not use a rifle that will kill an animal when everything goes right; you should use one that will do the job when everything goes wrong." -Bob Hagel

    “LETS GO BRANDON”

  4. #4
    Boolit Grand Master Tatume's Avatar
    Join Date
    Jan 2010
    Location
    VA
    Posts
    5,574
    Try this. Using a ballistics calculator (I like JBM) Pick a reasonable velocity and other data, and put in three BC estimates. For a 43 caliber bullet at 1400 fps I used a 100 yard zero and 50 yard interval, with BC values of 0.15, 0.20 & 0.25. The drops in inches at 50 and 200 yards tell the story.

    0.15 4.0 -12.7
    0.20 3.7 -11.5
    0.25 3.5 -10.7

    The differences aren't enough to amount to a hill of legumes. So why sweat it?

  5. #5
    Boolit Buddy
    Join Date
    Oct 2016
    Location
    Superstition Mountains
    Posts
    208

    Cool

    The OP wants help with determining a BC for his bullet for use at the higher velocity from a rifle, not a handgun. Perhaps he’s interested in remaining velocity or potential wind drift, we don’t know. He really doesn’t need to be told he’s wasting his time.



    .

  6. #6
    Boolit Buddy memtb's Avatar
    Join Date
    Sep 2016
    Location
    Winchester,Wy.
    Posts
    495
    [QUOTE=PositiveCaster;5202225]The OP wants help with determining a BC for his bullet for use at the higher velocity from a rifle, not a handgun. Perhaps he’s interested in remaining velocity or potential wind drift, we don’t know. He really doesn’t need to be told he’s wasting his time.


    “If” that was directed toward my post.....careful reading and comprehension would show that, I just recently had the same question! Though my velocities would only be around 1500 fps for 400 grainers from my 460 S&W!

    “If” it wasn’t directed to me....then my apologizes are offered! memtb
    Last edited by memtb; 06-05-2021 at 02:27 PM.
    You should not use a rifle that will kill an animal when everything goes right; you should use one that will do the job when everything goes wrong." -Bob Hagel

    “LETS GO BRANDON”

  7. #7
    Boolit Grand Master Tatume's Avatar
    Join Date
    Jan 2010
    Location
    VA
    Posts
    5,574
    Don't worry about it. It was directed at me, and isn't worth any bother.
    Last edited by Tatume; 06-05-2021 at 03:26 PM.

  8. #8
    Boolit Buddy
    Join Date
    Apr 2015
    Posts
    156
    I'm working on a load that will be Colorado legal for big game. The rifle is a CVA Scout with a 22" barrel. I have a chronograph but I don't trust myself to shoot over it at 50 or 100.

    For a rifle It will need to have at least 1000 fpe at 100 yards. If i use 44 mag load data for the 320 LBT in an 8.5" barreled pistol my max would be 1310 with Ramshot Enforcer. (the powder I know I'll have on hand before the season in September) I prefer H110 for the 44 mag but I have only a small amount and probably not enough to work up the load.

    I would like to run the ballistics with the actual BC for the LBT but without it, my compromise on the BC is using the BC for a 300 grain XTP. I think it will be safe to go with that as far as accurate data goes although the LBT does have a pretty wide meplat. According to Point Blank I need to start it at 1385 fps to get to 1014 fpe at 100 yards. So I only need to pick up 75 fps to get there and I think it will be easy to exceed that.

    I shoulda included this explanation with my original post. My apologies for neglecting to explain up front.

  9. #9
    Boolit Master
    Join Date
    Feb 2012
    Location
    Blackwater, Virginia
    Posts
    711
    longcruise; I just looked at some charts similar to your bullet design & it appears that with what I see your're really close at your stated 1385 fps to maintain that velocity of 1014 at 100 yds. 1385 may be slightly over the must have.

  10. #10
    Boolit Grand Master Tatume's Avatar
    Join Date
    Jan 2010
    Location
    VA
    Posts
    5,574
    The BC for the 300 gr XTP is 0.245, and I think that is very optimistic to the point of being unrealistic. A more realistic estimate was given by memtb above, 0.20. Personally, I think it's likely to be less than that.

    The best approach is probably to forget about BC altogether. Most are based on the G1 model, which works for well-streamlined projectiles, but is not a good approximation for your bullet. Better would be to overcome your fear of shooting the chronograph and record some actual speeds at 100 yards. If you can keep your shots on a six-inch circle you can do it. When you find a load that satisfies the objective, write down the data and the calculation on a card and laminate it. The card will probably satisfy your game warden, who should be impressed with your sincere desire to obey the law.
    Last edited by Tatume; 06-05-2021 at 05:51 PM.

  11. #11
    Boolit Master gpidaho's Avatar
    Join Date
    May 2014
    Location
    Beautiful Idaho
    Posts
    2,644
    longcruise: If your anywhere near a fellow Boolits member with a LabRadar that's your answer to the chrono at 100yrds. They can be programmed to give velocity at different distances. If you happen to be from S.W. Idaho we can use mine. Gp

  12. #12
    I'm A Honcho!
    bluejay75's Avatar
    Join Date
    Mar 2017
    Posts
    1,752
    I use .200 as a default BC with most of my FN boolits in almost every caliber I use...if its a short boolit. If its a long boolit (usually heavy for caliber boolits) I use .250. Out to 300 yards if you run in a Ballistic calculator you will be within 1 inch of the actual drops either direction.

    Play with this calculator and you will see what Im talking about. Use HP or RN as your nose profile.

    http://gundata.org/ballistic-coefficient-calculator/
    You never know how you rank amongst men 'til you have seen what will break another man.
    The original "Bluejay" US Army/ US Navy 1945-1970.

  13. #13
    Boolit Buddy
    Join Date
    Dec 2016
    Posts
    280
    If you have a chrono couldn't you just get your velocity then zero at 25, move to 50, 100 etc and then use your observed drops to work the numbers backwards in Hodgdon's or a similar ballistic program?

  14. #14
    Boolit Master



    Join Date
    Oct 2008
    Location
    1720 miles East of Wall Drug, North of Cooperstown, NY
    Posts
    1,082
    Longcruise, you say you have a chronograph and you are working/listing pistol data for a rifle with a 22" barrel and no cylinder gap? Come on man, get off your butt and find what the load does from your rifle. You need to educate yourself on what your load will do from your rifle. Only you have the particular rifle, load, bullet and items needed to find all your answers.

    If you do not trust yourself to shot at a target to verify zero and then set your Crony up in front of a proven zero, then how do you even expect to be able to hit an Elk with Elk fever in play?

    BC varies dependent on velocity of the bullet. Oh that's right you have no idea what the velocity from your listed rifle is. To bad you don't have a crony, oh wait you do!
    Last edited by Screwbolts; 06-06-2021 at 07:55 AM.
    ΜΟΛΩΝ ΛΑΒΕ
    Je suis Charlie
    Remember Lavoy!
    I'll cling to my God and my guns, and you can keep the "Change".

  15. #15
    Boolit Buddy memtb's Avatar
    Join Date
    Sep 2016
    Location
    Winchester,Wy.
    Posts
    495
    longcruise, Don’t give up on the forum......some of us are willing to help you. Not all of us are self-righteous, judgmental individuals.....that have forgotten what it was like to “not” have all of the answers! memtb
    You should not use a rifle that will kill an animal when everything goes right; you should use one that will do the job when everything goes wrong." -Bob Hagel

    “LETS GO BRANDON”

  16. #16
    Boolit Buddy
    Join Date
    Apr 2015
    Posts
    156
    Quote Originally Posted by Screwbolts View Post
    Longcruise, you say you have a chronograph and you are working/listing pistol data for a rifle with a 22" barrel and no cylinder gap? Come on man, get off your butt and find what the load does from your rifle. You need to educate yourself on what your load will do from your rifle. Only you have the particular rifle, load, bullet and items needed to find all your answers.

    If you do not trust yourself to shot at a target to verify zero and then set your Crony up in front of a proven zero, then how do you even expect to be able to hit an Elk with Elk fever in play?

    BC varies dependent on velocity of the bullet. Oh that's right you have no idea what the velocity from your listed rifle is. To bad you don't have a crony, oh wait you do!
    Wow! Condescension beyond comprehension! As well as indicative of a problem with reading comprehension. ��

    So, one point at a time. The reference to pistol data was clearly for comparison and extrapolation to probable results from a 22" barrel.

    Get off my butt?? That's a joke. This post is the beginning of the process. And it's not one viewed by myself as objectionable work but (one "t") fun times on and off the range.

    I'll definitely not be setting up the chronograph at distance.

    Tatume saw exactly what the whole point of the exercise is. It’s to establish a clear illustration of the legality of the firearm/load in case it is questioned in the field.

    You seem to reaching pretty far for your ad hominens. After all it was just a simple question about a BC in case someone might have the information at hand. I could care less how the BC might vary at velocity. Like I said, the point is to establish the legality of the combo. A WCO in the field might question the legality but they won't be quibbling over the variations of a BC at velocity if it is legitimately supported by its source.

    I never suggested that I would be shooting at an elk.

    I'm not concerned with the adequacy of the 44 in terms of how it will perform. If it weren't for the legality aspect there would be no question.


    I appreciate the well thought out suggestions that have been offered here. Thanks so much for those.

  17. #17
    Boolit Buddy
    Join Date
    Jun 2013
    Posts
    445
    As gpidaho mentioned LabRadar would be ideal for your problem. It’s pretty expensive tool but you might find someone close by who owns one.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check