Warm weather vs. Cold weather

[Rum River]

What differences in performance have shooters seen depending on temperature?

I have a .54 Great Plains with a 32" twist. Best conical load is a 365gr. T/C Maxi-Ball with 120grs. of Goex FFg. I know that's a lot of powder, but it sure gets the attention on the range!

Anyway, six shots at 100 yds. were a 3 1/2 group outside measurement on a 70 degree sunny day.

Yesterday in 40 degrees with 15-20 mph winds, the rifle and components were outside for about 3 hours before shooting. The best 'group' (if you want to call it that, more of a random scattering) was 12 inches, with one group going over 18".

I don't believe the wind is a factor. The bench was out in the breeze, but my range is fired down an 'alley' in the forest, with the trees beginning at the 50 yard mark. Where the targets are hung is quite calm.

Is it possible the bullets were just cold enough they wouldn't slug up to the bore? The weather for the muzzle season here could easily be below zero, I have to find the answer long before then.

[quickdtoo]

In my limited experience with lubed conicals, the temp has more to do with the lube you are using than the projectile itself.

[filmokentucky]

That's my experience, too. Some lubes will stiffen up to the point of being almost useless. One solution is to carry the lube in an inside pocket
where body heat will keep it soft. For roundball, I've had good luck with Ox-Yoke Originals Wonder Patches. They seem impervious to temperature
changes and they don't slime up your fingers, either.

[crow_feather]

Have you checked your bore for lead buildup?  That can cause a wide dispersion of bullets.  You might try pushing a green dish scrubber type thing - or some fine steel wool down the bore to see if you have lead in there.

Also, with the heavy charge and harder lead because of the colder temp, you might be stripping the lead bullets in that fast twist bore.  Try less powder and see if that doesn't make a difference.

Best of luck,

C F

[Rum River]

Thanks for the responses, I'll follow up on all of your suggestions.

[harryo]

Yesterday in 40 degrees with 15-20 mph winds, the rifle and components were outside for about 3 hours before shooting. The best 'group' (if you want to call it that, more of a random scattering) was 12 inches, with one group going over 18".

I don't believe the wind is a factor. The bench was out in the breeze, but my range is fired down an 'alley' in the forest, with the trees beginning at the 50 yard mark. Where the targets are hung is quite calm.

 would bet the wind was the major factor in your groups opening up.  Muzzleloading projectiles are relatively slow when compared to modern centerfire cartridges so they are in flight a longer time before they hit the target.  This coupled with the large side profile of the projectilel can cause some major wind drift.

I would estimate your maxiball, with that amount of powder, left the muzzle at somewhere around 1500-1600 fps.  With a 20 mph crosswind, you could have 16-18" of bullet drift at 100 yds.  You said the last 50 yds was sheltered but if the first 50 yds was exposed to wind, you can see that you could still have a fair amount of drift.  If the winds are gusting over 20 mph, there would be even more potential for drift.  You said that the range went from the open to a lane through a forested area at 50 yds.  Wind can "pile up" where it hits a solid, or semi-solid object, such as a thick stand of trees, and cause a swirling crosswind that is actually faster than the average wind speed in the open area.  This can play havoc with your projectile.

[Rum River]

Easy enough to try it again on a calm day. Another reason to burn powder!

[Longcruise]

Hi Rum, I doubt if the wind was doing all that much to your group, but the comments above regarding wind should be considered carefully.

I think that the single biggest factor effecting ml performance on a day to day weather basis is humidity.

On days with low humidity you need to swab your bore with a fairly wet patch between shots.  Even on a high humidity day, maxi balls are notorious for forming a crud ring just below the point where they sit on the powder.  the more you shoot the bigger and longer the crud ring gets.  Add low humidity and the crud ring gets harder and harder with each shot.

I first noticed this some years back when sighting in my TC >50 with maxi balls.  The more I shot the worse the accuracy became.  I also noticed that the maxi was seating a bit shallower in the barrel after each shot according to my ramrod mark.  I was not swabbing between shots or even between groups.  Figured if the conical would load, then all was well.  When I findaly did swab I noticed a pretty tight and long constriction in the bore just above the "chamber".  It was a ring of very hard crud/powder fouling.  It was so persistent it took two very wet patches to bust it out of there.  After that I swabbed after each shot and presto!  My groups were back to normal.

This same thing happens but to a lesser extent with round balls.  For some reason a flat base conical causes a larger crud ring.  Also, most round ball shooters swab between shots or at least more often than conical shooters.

Here's a probable scenario of the wind effect on your maxi at 10 mph.  Just double for 20 mph, etc.  I had to assume a BC but it's probably pretty close.  Minor variations in BC and velocity will not effect a chart of this bullet very much

Name: .50 Cal, TC Maxi, 370 grn
Ballistic Coeff: 0.200
Bullet Weight: 370
Velocity: 1550
Target Distance: 250
Scope Height: 1.500
Temperature: 70
Altitude: 500

Ballistic Data
~~~~~~~~~~~~~~~
  Range  Elevation  Velocity   Energy     ETA         Drop      Max Y  10mph Wind Def
  0 yds   -1.50 in  1550 fps  1974 fpe  0.000 sec    0.00 in  -1.50 in   -0.00 in
 25 yds    4.49 in  1475 fps  1788 fpe  0.049 sec    0.46 in  -0.48 in    0.16 in
 50 yds    9.48 in  1405 fps  1622 fpe  0.101 sec    1.92 in  -0.10 in    0.80 in
 75 yds   13.36 in  1340 fps  1476 fpe  0.156 sec    4.49 in   0.59 in    1.95 in
100 yds   16.04 in  1280 fps  1345 fpe  0.214 sec    8.26 in   1.62 in    3.52 in
125 yds   17.41 in  1224 fps  1231 fpe  0.273 sec   13.35 in   3.03 in    5.52 in
150 yds   17.30 in  1174 fps  1133 fpe  0.336 sec   19.90 in   4.89 in    8.03 in

[Good time Charlie]

This feller was shooting at 70 degrees and 40 degrees. This is not enough temp. change to have anything  to do with his gropes. If we were talking about zero degrees or less maybe. But nothing is freezing at 40 degrees. Believe me it is the wind!

[Rum River]

I haven't had a chance to get back to the range yet, but I may have found another piece of the puzzle.

For the sheer hell of it I got my calipers out and started checking bullets, the diameter of the remaining 15 bullets in the new box I was using varied as much as five to six thousandths.

I had not checked those I used the day I shot the good groups. I'll sort these by diameter before I try again and see if there's a difference.

[harryo]

Here's a probable scenario of the wind effect on your maxi at 10 mph.  Just double for 20 mph, etc.  I had to assume a BC but it's probably pretty close.  Minor variations in BC and velocity will not effect a chart of this bullet very much

Name: .50 Cal, TC Maxi, 370 grn
Ballistic Coeff: 0.200
Bullet Weight: 370
Velocity: 1550
Target Distance: 250
Scope Height: 1.500
Temperature: 70
Altitude: 500
quote]

The ballistic coefficient of the 370 grn TC Maxi is .095.  That conical will drift 16-18" at 100 yds with 20 mph crosswinds.  I have seen it and experienced it.

[Longcruise]

The ballistic coefficient of the 370 grn TC Maxi is .095. That conical will drift 16-18" at 100 yds with 20 mph crosswinds. I have seen it and experienced it.

Figures to about 15" in a perfect 90deg crosswind with a BC of .095.

I'm skeptical on the .095 BC though.  Where did you get that figure?  Not saying your wrong on it, just expected a higher number.

[harryo]

[quote="LongcruiseFigures to about 15" in a perfect 90deg crosswind with a BC of .095.

I'm skeptical on the .095 BC though.  Where did you get that figure?  Not saying your wrong on it, just expected a higher number.[/quote]

Lyman Black Powder Handbook & Loading Manual--2nd Edition

[Longcruise]

Lyman Black Powder Handbook & Loading Manual--2nd Edition

Harryo, thanks for the reference.  That's a much lower BC than I'd have expected.

[Rum River]

Went out again and tried at 100yds with no wind, same poor results. I do not dispute that the wind is a factor. In my case I believe I have other serious problems as well.

I tried yet another bullet, in this case a 'Swiftkik' in 365gr. The same weight as the T/C Maxi-Ball that shot so well on a 70 degree day. Anyway, the box said 'sized to .541"', and I confirmed that with calipers. When I went to load in a clean, dry barrel, the bullet was so loose it dropped into the muzzle beyond the reach of my short starter. When I used my brass range rod to seat, the weight of the ramrod pushed that bullet all the way to the powder. Accuracy stunk, even at 25yds.

Got home that night, took one of the T/C Maxi-Ball, and verified the diameter was .538". Put some smooth jaws in my vise and swaged it until it measured .555". Ran that into the rifle until just short of the chamber area, popped it out with the CO2 discharger into a wad of soft cloth. When I measured that it shows a bore diameter to the bottom of the grooves of .551".

This means that Maxi has got to slug up .013". Man alive, the .533" Minie ball I've tried was expected to slug up .018"! To me that sounds like an awful lot to expect.

Who out there has slugged their bore and knows how much their particular bullet is 'bumping up' to fully engage the rifling?

[Longcruise]

Rum, you are on the right track with this fit problem.

The minie can slug up better because of the hollow base and the skirt.  the down side is when you shoot them over heavy charges they come out the bore and open the skirt up like a cone which then ruins accuracy too.  The buffaloe bullets have a thicker skirt on their hollow base and might solve that problem.  All in all, I prefer solid base but that's just my preference.

These loose fitting slugs can lead to problems in the field when the slug slides up and down the bore while you carry your rifle.  That has been discussed here in the past and many say no problem but I have seen it twice with my own eyes :eek:  These incidents were what caused me and several of my shooting buddys to go to round balls only for hunting.  If you only sit on stand it's probably not a big deal but if you hunt the mountain country like we do, there is a lot of movement of the gun as you travel.

Thge most accurate conical I ever shot was with my TC .50 and the slug was a 450 grain bullet for the 5-70 govt round.  It was sized down to I beleive about .504.  It was a fairly tight fit and it did shoot with fine accuracy.  with 80 grains of ff it pounded the shooter pretty good :shock:   But, I relate that story to highlight the importance of bullet fit.  My .50 maxi mold throws slugs that fit somewhat tight but not near as tight as the .50-70.  And, they do not shoot with as much accuracy.

I'll give you some unsolicited and possibly unwanted advice at my own risk :grin: ;  Lose the fast twist barrel!  Especially in .54 caliber!  The .54 conicals have lousy sectional density and are very heavy resulting in severe recoil, especially with the Lyman GP style butt plate :shock:   Get a replacement barrel with round ball twist in a .50 or .54 caliber and go to round balls.  They are great for plinking and match shooting and more than adequate for hunting.  Go .50 if your a deer only hunter or only shoot targets and .54 if you pursue game larger than deer.