jaw3

Is there a source that recommends velocity for a given weight/type bullet.
If I load a 330 gr Harvester sabot with 90 gr 777 I get about 1550 fps.
If I load a 280 gr Harvester sabot with 90 gr 777 I get about 1650 fps. I'm just starting this quest for
velocity, ft-lbs accuracy quest, but wonder if the increase charge is worth the extra vel or should the
defining fact be when the group starts to open?
Any thoughts?
Regards,

sabotloader

jaw3

There are several handi-dandi free ballistic calculators out there that will answer your question - if you do a simple search for a Ballistic Calcualtor you will come up with several sites.

I have a program that does it for me so I do not have addresses off hand but several people will visit this post and get you some.

cayugad

To me, there is a point of diminished returns when it comes to powder charges. You will find as with most projectiles, there is one point where accuracy is the best. If you add more powder the accuracy will fail or less powder and you might not get as good.

The trick is start low and work up. With most sabots I start at 80 grains of powder and start shooting groups. That's one reason I am not a believer in getting too excited about scopes and sights until I have the actual load worked up. If you have a good load at 80 grains, move up to 85, 90, 95, etc.. at some point the accuracy will get better or worse. That is the point you want to reach. Or you might come to a point where you do not like the recoil anymore if you are sensative in that area.

If all your looking for is velocity, then you need to get a chronograph. Start shooting and adding powder. There will come a point that even if you add more powder the gain in velocity is not worth the increase in powder. That's diminished returns.

lemoyne

Jaw3
To answer your question accurately we need to know what the load is going to be used for;
for and what caliber you will be shooting.
The two most common situations would be deer and boar if you live where there are some also target shooting a god part of the year. Will assume a 50 cal inline as its the most common.
If you wish to set up for long range some thing like a 200gr SW with 120 gr of Blackhorn this load gives about 2145 average FPSin one of my guns I use the 250 SW in the other with 120 gr Blackhorn fora 2075 average FPS if you like 777-FFF it gives about the same velocity but I find it much harder to get equalaccuracy with that heavy a load and scrubbing out the crud ring every shot wont happen to me any more. Lee

Semisane

Hey jaw3, here's the calculator I use. It's real simple to play around with. http://www.handloads.com/calc/

Based on your statements about the velocities you are getting with those two bullets I assume you have access to a chronograph (unless you're going by book figures). I've used my chrono to track velocity increases as I increased loads in 5 or 10 grain increments and it's fairly easy to identify the point where the velocity stops increasing even though you increased the charge. When that happens you've found the maximum "usable" charge. Most of the time I find the most accurate loadsomewhere below the maximum usablecharge - but not always. Sometimes the maxusable load is themost accurate one.

On at least one occasion I had accuracy stay about the same over a wide spread of charges (95, 100, 105, 110 and 115 grains of powder), but velocity increased only between 95 & 100 and 100 & 105 grains of powder,then started decreasing at 110 and 115 (even though accuracy stayed about the same).

gleason.chapman

You need to know the ballistic coefficient of the bullet. Usually on the manufacturer's web site or "Google is your best friend". Example lets do 330g Harvester on their web site, here it is:

http://www.harvestermuzzleloading.com/index.php?view=article&catid=3%3Asaber-tooth&id=3%3Asaber-tooth-load-data&option=com_content&Itemid=4

You can see by the load data that 10g of powder is getting you only 50 more fps, approximately. The
Saber Tooth is shaped like a XTP, so I think it is going to have a ballistic Coefficient like a 330g XTP

http://www.nfa.ca/nfafiles/cfjarchive/ballistics/bcchart.doc#C45

which is .180 for the 300g XTP, so drop the values .180, 330 and 1550 in a balistic program and sight in at 145 yards for about a 3" high at 100.

Here is a Screencast on how to run a ballistics program:

http://screencast.com/t/NGC51UoF2Sg

Chap

Screwbolts

Chappie"s Guesstimate of BC is very very close if you were shooting them at 2100 FPS!, I will take the time later to transfer a post from another site to here where I shot the 330's with 2 different charges and used a crony at the bench and backstop.

Using "load from a disc" BC calculator based on known velocity at the bench and 103 yard distance the BC for a load that averaged 2110FPS at the muzzle was .180/ then normalized by conditions at the time it was shot to a BC of .178.

Using the same program but with a Muzzle velocity average of 1715 FPS the BC was .197/ normalized by conditions to .195.

Yes it is a known Fact that the BC of a projectile changes with Velocity, take a look at Seirra's web site they list the BC at 4 different velocity's for some of their projos!

IMHO you are shooting 2 of the finest Hard cast Boolitzs ever made to cleanly harvest anything on this Globe.

Tell us about your Rifle, will it shot BH209? My 22" Knight T-bolt crony's 1778 FPS average with 105 grv of BH209.

IMHO 1700 to 1800 will be the best velocity to shoot these wide Metplat Boolitzs. but you can't go wrong at 1550 to 1650 either! the BC will be higher, You don't need hyper velocity with a properly designed Boolit. The Fellow that actualy made the molds for these Bullets (Veral Smith ) told me that a striking velocity of 1500 would be a ideal, and let you eat right up to the Boolit hole. to drive them faster would just ruen a lot of good eaten. The folks that shot these out of Pistols find that 1000 to 1275 FPS is egualy deadly. It is also known that to drive them to fast causes a diminishing return on results.

IMHO, The Boolit you have described is in it's perfect shape before it leaves the muzzle. It has been said that Craig Bodington loves to find a bullet with a nice mushroom and long shank. Well, the WFN/LFN Hard Cast Boolit, is just that! Cast Boolit Shooters already know that there boolit is just what Craig likes, only it started life that way and doesn't have to go threw some uncontroled varying medium to make it such. A nice Mushroom is nothing but a wide metplat. IMHO The Boolitzs you have choosen are perfect for all occasions. they already meet CB's perfect bullet criteria and they woun't change shape because they are Hard cast, as they travel threw any game animal. They will just work like CB's perfect Boolit.

Screwbolts

This is a post I have moved from a Smokeless board but I think the BC is relevant on this thread.

If you need a tighter fit with the LBTs just knurl them between to files to what ever diameter you would like.

This is a group I fired last Mon. My LBTHC in SBH sabot as cast. Shots 3 and 4 I realized I had changed my hold on the rifle, 1-3 were chronograph at the backstop 4-6 were with the crono at the bench. 103 yards between the chronograph placements readings. BC worked out to .180, adjusted to .178 by weather conditions, this is from Load from a disk program. This load was 6.5 of 5744 not 7.5 as the paper shows. ( LEE .5 CC dipper of 5744 )

These groups were fired from a gun that had been shot 7 times prior to this shooting since cleaning. No cleaning or patching of any kind was done, to shot these groups.



This is a load of 33 gr. of 4759. My LBT HC SBH as cast. Shots 1-3 were read at the bench, shots 4-6 were at the target, only got 1 reading because of to much shade I believe. BC worked out to be .197 adjusted to .195 after all condition data was entered. 33gr. 4759 is almost exactly what 105 gr of BH209 gets for speed. 105 gr. of BH209 reads 1778 FPS



This is a photo from my bench to the 103 yard back stop. 10 cu' freezer full of sand, my 150 yard backstop freezer is behind it but a downed tree has tipped it off its mount so it isn't visible. I need to remove the tree and reset the freezer.

jaw3

First thanks for all the inputs. I have a lot of studying to do.
More info. I'm using a TC omega .50 cal. I've have taken a FL hog and a NJ
deer with 90 gr 777 with 330 gr .45 cal .50 cal sabot P/n H35033. I had worked up the load for accuracy. But since have been using a Chrony to balance vel and accuracy. I just figured I'd like a go to load that will deal with 90 lb deer or up to a tougher hog. So far so good. Didn't get a pic of hog wound, but here is entrance on doe.
[IMG]http://i724.photobucket.com/albums/ww245/jaw3njfl/DCP_4147.jpg
Thanks again for all the input and insight.
Regards,

bronko22000

Jaw3- I pretty much go along with what Cayugad is saying. Personally, I am not too much concerned about velocity- to a point. I know increased velocity translates into increased energy (E=MCsquared). For hunting when I reach a rifle/bullet's most accurate combination with an acceptable velocity, that is what I use in that rifle.
Any increase in velocity results in wasted powder, more recoil and reduced accuracy.
Speed is great so long as you have the accompanying accuracy. Otherwise you will just miss your target faster.
But Hey - that's why we play with our rifles. To squeeze every ounce of accuracy we can out of them.
Have fun in your search for the ultimate load.