November 14, 2009, 10:38 AM
What is the optimal barrel length for today's inline's? I am looking to get into muzzleload hunting and like shorter barrels where possible, but is there a big difference between say a 24" vs 28" barrel?
November 14, 2009, 07:09 PM
I don't think that the barrel length makes too much of a difference at normal hunting ranges under ~150 yards.
The caliber & weight of the bullet and powder charge that are selected also contribute to a barrel's maximum range.
And when someone really wants to reach out to the more extreme BP hunting ranges then they usually choose a long range hunter model with a longer 28 inch barrel.
But for most practical hunting purposes, a 4 inch difference in barrel length shouldn't make too much of a difference.
To compare, I'll use a 300 grain muzzleloading projectile at 2000 fps, using a static BC of .200, a quite healthy load from any muzzleloader, generous in lethality but not in range. Using a 6 inch kill zone, the maximum point blank range is about 185 yards. Just a 10 mph direct cross wind can blow your bullet about 10 inches to the side of your crosshairs at that range, so wind management may already be an issue for us.
For starters, let’s look at what basic, .50 caliber inline muzzleloading trajectory is. A .45 caliber, 250 grain projectile out of an inline muzzleloader will typically have about 1800 fps at the muzzle with 100 grains of propellant by volume, or two pellets. The static ballistic coefficient is in the area of .190 for a 250 grain saboted projectile. These numbers are far from absolutes, just very rough guides. One individual rifle may have significantly more or less velocity, and not all propellants give the same velocities. Barometric pressure, scope height, and temperature all change things, so the following numbers are broad generalizations, not absolutes.
We are using deer hunting as an example, as it is the most common application. Most calculations for effective point black range use a six inch kill zone as the basis, though contingent on body size the actual kill zone of a deer may be nine or ten inches. Deer hardly stop and freeze perfectly broadside at known ranges, though, so any angle of the deer can only reduce our chances at completely confident double-lung, double shoulder and perfect shot placement.
Sighted in three inches high at 100 yards under standard conditions with 1.5 inch scope height, our 6 inch kill maximum point blank range for this load is about 167 yards. When using a center of the body hold, there is no point in the flight path of our bullet where the point of impact will exceed three inches high or three inches low from our point of aim.
Wind very quickly becomes a factor. At just 150 yards, a 10mph breeze can move our bullet over seven and one half inches. Though gravity is a known quantity, the precise effect of wind drift on our bullet from muzzle to target on any single shot can only be estimated. The solution to doping the wind is straightforward; we need to go out and shoot in the wind at range to become more aware of what it does. Jack O’Connor liked the self-imposed restriction of a top of the shoulder hold, meaning in this case a 210 yard shot, which drops 11.67 inches into the chest. Now, we need to be even more aware of the wind, as that 10 mph crosswind can move our bullet 15.23 inches, larger than the kill zone of most deer itself. We are still assuming a perfectly stationary animal, which is not always the case.
While there are opinions galore, the complete confidence of an individual to place a bullet where it counts is no opinion at all. We either know it, or we do not. Under ideal conditions with a good, stable shooting position, 210 yards for a trajectory of this type is the outer limit of an O’Connor-esque ethical shot. We can improve things, though.
We are changing things by using a heavier bullet, the 290 grain Barnes Spitfire T-EZ flatbase, with a published B.C. of .223. Further, we are going to up the velocity by using 110 grains by volume of Blackhorn 209 to about 1950 fps. A good chronograph shows what we are getting out of our specific rifle. Now, we have substantially more to work with.
Our 6 inch kill zone MPBR is now 184 yards. Top of the shoulder range, ala O’Connor, is 230 yards (11.57 in. drop from P.O.A). Wind remains a major factor, but a bit less so. Even though we have swarms of referees that can’t always tell if a football made it across the goal line, we are now hunting at more than two times the length of a football field, at a range when no one I know could possibly tell the difference between a button buck and a doe. Under ideal conditions with a steady rest, the perfect broadside shot that we are completely confident of making poses no problem. Add in wind, animal movement, a less than perfect rest, or something other than that picturebook completely broadside shot and the experienced hunter adapts accordingly.
Why not farther? Well, that is the responsibility of the individual.....
November 15, 2009, 07:49 AM
Great thread svenrh. Articap, thanks for the(as usual) very informative,excellent response. Agree that under normal hunting ranges the 4" barrel length will not make a difference. Why not farther? Well, thats the responsibilty of the individual... IMO, when it comes to hunting, doesn`t matter what weapon we choose, this is ALWAYS the main factor. I`ve always played 'catch up' to about every weapon I`ve shot. Meaning, the weapon was more accurate than me. Punching paper out to 200-250yds is different then shooting at game. Wounding paper doesn`t keep me up at night:). Alot of guys think cause they take their rifle out and shoot paper out to say 150yds. they`re good at that distance for hunting deer at the same. Don`t consider the things stated in Articaps post i.e. wind. Also(unless I missed it)we don`t consider terrain. Zero at say 100yds on flat ground. Hit the paper 5 outa 5. Then go shoot same distance at about a 15-20% incline or decline. Different POI. Bow hunters know this well as its more prevalent in the arch of an arrow. Zero your rifle, practice alot, shooting at different scenario`s of your hunting terrain. Whether shooting a 24 or 28" barrel length, knowing OUR capabilities and NOT shooting beyond them at game is the responsibilty of the person pulling the trigger.
November 15, 2009, 09:22 AM
I have inline muzzleloaders with barrel lengths from 22" to 28." IME: A few inches of barrel length makes very little difference in velocity unless very heavy charges of black powder or a substitute are used.
I sometimes fire my guns after legal game shooting times in the evenings to unload the gun or check the zero. There is absolutely no muzzle flash from my 22" and 24" barrels when using 100 grains of Pyrodex or two 50 grain Pyrodex pellets along with the 240 .430 grain XTP bullet.
Put 150 grains of Pyrodex RS or three 50 grain Pyrodex pellets in a 22" or 24" barrel under the same conditions and there is a 4-6' sheet of sparks and flame from the muzzle.
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