first time with a chronograph

[doulos]

Ive had a Pro Chrono chronograph sitting in a box new and unused for a while now and decided to finally try it out. I didn't have a lot of time, but I just had to try it.
 I wasn't exactly sure how far away from the muzzle to set it. So I started about 15 feet. I loaded 100 grains FFG Swiss in a .58 cal Stith Hawken with a .570 Hornady over some Walmart pillow ticking (7to 1 water and ballistol) and let er rip.
First shots was 1660 (clean barrel) the rest of the string were between 1669 and 1718 fps (without cleaning)  Well so much for the .58 cal being a slow poke.
To hear some of these writers you would think you couldn't approach those velocities with 100 grains of powder.

Well anyways  I thought the velocity variation might be due to my patches sailing over the screens . So i moved it back to about 25 ft and velocities were a bit higher. All over 1700 except one at 1690. But still a lot of variation from low shot to high about 55fps. Does this seem high?
Could this high variation be from my patches.  The few i checked seemed pretty frayed on the outside but no burn through in the center.
My usual Goex FFg load I use for hunting 110 grains was more consistent in velocity but alot slower. 4 shots 1592,1606,1612,and 1598. And this is actually pretty soft shooting in this heavy gun.
I'm wondering if the variation is from my patching or me hurrying my loading procedure?
Just curious from those who chrono their loads.

[Standing Bear]

Lots of potential causes. 

Bench shooters I spent time with 20+ years ago were real particular about the seating pressure of ball on powder.  Just a thought. 

Also an easy thing to check would be using different lubes.  My .40 flinter was chronoing just under 20 fps variations.

I understand the difference between Swiss and Goex velocities.

TC

[frenchman]

keep us posted, just bought one, but will only be able to use it this next spring, i also shoot mostly patches and balls butt will try some maxi , minies , minier's not a ton of them. Just for my personal info just curious.

Have you tried placing a carboard in front of the chrono to stop the patch , i dont think there would be that much of a different , just to catch the velocity

[smylee grouch]

Doulos, My 58 flinter gets 1900 with 110 gr. Swiss  2f and a greased 20/1000 patch. I get 1450 with 110 gr. GOEX   2f.  Recoil with the Swiss load was quite stiff so I cut it back to about 90/95   2f  Swiss and get about the same vel. as the 110 GOEX load. Turns deer inside out.    Smylee

[doulos]

Smylee
I do know most of the data supplied by some writers on the internet is much slower for the .58 cal than what I saw today.
 I was also actually surprised the Swiss was that much faster
My second string with 100 grains Swiss all the shots except one at 1690 were in the 1720-45 range.
this was with a 34 inch Colerain barrel. How long is the barrel on your flinter?

[smylee grouch]

Doulos, my barrel is a oct./round 32" made by John Getz. English style Pat. breech. It is a real good shooting round bottom cuts and easy to keep clean. Best results are with a tight fitting greased patch.    Smylee

[Daryl]

Powder today delivers higher speeds than the powder that was used in Lyman's book. This is very evident in the .58 cal. My little Musketoon, with only 24" of barrel, achieved 1,308fps with a mere 75gr. 2F. According to the "book" it should have been getting somehting like 1,077fps.

Moving the screens back will ALWAYS show a reduction in speed. It is impossible for the ball to accellerate once it leaves the muzzle as all propulsion is gone.  The reason you showed higher speeds, is due to fouling building in the gooves, tightening the ball and patch combination, resisting the powder's pressure and causing it to deliver more energy to the ball - hanse, higher speeds.

The variation shot to shot is due to the same thing- if the combination was tighter, the velocity extremes would be closer, shot to shot.  Rifles and smoothbores, for that matter, will deliver very close shot to shot velcoity speads with certain loads, other loads showing more spread. A while back, I printed out the velcity testing I did with my .58 Hawken, a heavy barreled S. Hawken Taylor built many years ago. I believe it had a Bill Large barrel, which I tested form 90gr. to 200gr. 2F, Meteor, C&H and GOEX or GOX - whatever it was. I've lost most of the data but still have some.

What was most intersting, was I also tested Bear's oil lubed patches. In all instances when lubed with the oil instead of spit, velocity spreads more than doubled. I used a .022" denim patch - (10oz. I assume), with a .575" ball. My best shot to shot strings had less than 10fps shot to shot variation.

doulos - your speeds are quite comendable. The Swiss powder you used is some 20% "better"/"hotter" than GOEX, BTW, judging by what Ross Seyfried printed about equivelent loads for regulating loads to shoot to the sights of antique rifles. With GOEX of today, those speeds, ie: 1,700fps should be achievable with 120gr. of 2F.

[doulos]

Daryl
I know your right about the increase in speed after moving the chrono. I was a bit perplexed but was suspecting fouling because I wasn't cleaning between shots. And an increase didn't make sense to me. But I wasn't sure if patches were interfering with the reads, this being my first chrono session ever.
How far do you set up from the muzzle?

[Daryl]

15 feet or whatever length the electrical cords will allow, up to 20feet, works well with all guns.  With pelters, you might want a shield in front of the first screen and not use the wires either, due to wads striking them and breaking out the plastic 'eye' cases.

The reason for not putting it closer than 15' is the muzzleblast on many guns will give/cause error readings.  At times, generally attributed with changing light conditions causing difficulty with the 'eyes' seeing the bullet or ball's passing, you'll see a reading that is too high, or too low compared to the other readings - that is what the edit button is for, to eliminate that from the 'list' of readings. 

Very loose loads that fry/burn up patches, will give wide and low velocity readings due to powder gas blowby. Clean barrel shots usually produce lower speeds than 'dirty' loads as well as less consistant readings, shot to shot - in my findings with my loads.

I've chronographed my .58 and .69 rifles with wiping between shots as opposed to shooting dirty. The ONLY way I got readings under 10fps between high and low recorded velocities in a 10 shot string, was when not wiping and using spit for lube - almost dripping wet with spit, btw.  At the time of those tests, spit was the only non-oil-based lube I used. For oil, I was using bear grease or marmot oil as well as barely starting the experiments with Neetsfoot oil.

[Herb]

Here I am shooting my .58 fullstock flintlock Hawken I built (Track's parts) at milk jugs at about 170 yards.  My chronograph is an Oehler 35P, and you see the armored light shields.  Patches or overpowder wads will break these, thus the armoring with tin.  The top orange shade was shot when I mistakenly set a trigger that wasn't a set trigger.  I put my screens at the limit of the cables, I suppose about 15 feet.

Extreme spread of 40 to 50 feet per second is not uncommon nor of much importance as far as I can tell.  Here are some targets I shot with a Bill Large barreled .58 Hawken when I was working up elk loads for Don.  On my computer screen there is a little gear at the top right which if you click on it comes up "tools".  Cllck on it again and you can zoom the picture up to 200 percent and read the targets.  The first shot with a clean bore is usually low in velocity.  Here 120 grains of Swiss 1 1/2 gave 1831 fs with 25 spread.  With my flint Hawken .58, the same load but Swiss 2 gave 1843 and 50.  But these heavy loads of Swiss foul the bore so bad that you have to wipe between shots.  So I don't use heavy Swiss loads.  These are 50 yard targets.

[Daryl]

Holding down the ctrl button on the keyboard and pushing the =+ key will also enlarge the picture - my PC does. Holding the ctrl button and pushing the -_ key reverses the process, making the pictures smaller.

[BrownBear]

Powder today delivers higher speeds than the powder that was used in Lyman's book. This is very evident in the .58 cal. My little Musketoon, with only 24" of barrel, achieved 1,308fps with a mere 75gr. 2F. According to the "book" it should have been getting somehting like 1,077fps.

I "figgered" that one out a while back.  I saw similar jumps in vels with .570 balls and ticking in 24, 26, 32 and 36" barrels using Goex, and assumed it was powder difference.  Then one night I was browsing and saw something interesting.  Lyman was using .560" balls in a barrel with .575" bore and .583" grooves.  I've never miked my barrels that close, but when I went back and reshot using .562" balls and ticking, I got results a whole lot closer to Lyman's.  It shows another benefit of tighter ball/patch combos if nothing else.

[Herb]

Daryl- thanks for that tip.  I did not know that and I bet you helped a lot of other folks, too.
BrownBear-You, also,  always have informed comments.  I am testing different patches in my .58 flintlock for an upcoming elk hunt, and what I am learning is that thinner patches, such as .010 OxYoke or even .015, don't hold enough lube to clean the bore as you seat the ball.  The bore feels gritty.  I think I have .020 OxYoke bulk patching on hand but can't find it.  I think it really only mikes about .018, maybe a little thinner, even.  I have used .022  cotton "duck canvas cloth red" from Wal Mart, UPC 8413221718 at $5.97 per yard, and it works with .562 balls with no OPW but I have to hammer the short starter to get .570 balls into the bore with it.  .575 I could not seat.  The duck comes in white or khaki but red patches are a lot easier to find on the ground.  Next trip out I will use Levi material, mine is about .020 and I think it is tighter weave than most other stuff.  I have used over powder wads (OPW) of wool or leather, but would like not to have to.  My load is 120 grains of Goex 2F but I will try 130 today.

[Daryl]

The CTRL button and Plus or Minus key was a hint from round ball in the building forum a while back. I found it works on my PC. I don't know if it works on the fruit computers.

[BrownBear]

I don't know if it works on the fruit computers.

Nope.  Dangit all anyway.