Chrono results and leading problems

djcantr · April 21, 2012, 03:43 PM

I loaded up a few hundred 115 grain LRN bullets from Missouri Bullet Co. into 9mm Luger cases with a CCI SP primer and 4.5 grains of Win 231. I shot a couple hundred of them from my Arcus 98DA today.

I recently bought a Chrony F1 and today was the first time I used it. I shot some of these 9mm reloads and these were the readings:

1151
1214
1218
1196
1284
1242
1205
1228
1235

I was surprised to have an average of over 1,200 fps when I was using a load in the middle of the suggested data (4.3 grains start and 4.8 grains max).

I came home and cleaned the pistol. It was leaded pretty bad. I take that back... It didn't look like it was leaded all that bad but it sure was a pain to remove. Took a good half hour to scrub the barrel and I mean I was seriously scrubbing. Probably ran that brush through a couple hundred times. The leading was in the last 1/4 to 1/3 of the muzzle end of the barrel. Close to the chamber was clean as a whistle. I decided to slug the bore. Below is a picture. The bullets are sized to .356". Where the lands dug into the bullet I'm measuring .350". The grooves did not contact the bullet. The picture is a bit misleading because the sides of the slugged bullet don't look to match the un-slugged bullet but that's just because they're sitting in my hand at a slightly different angle.

The bullets are 18 BHN. Should I try loading them at 4.8 grains so the base of the bullet maybe seals better in the grooves? I'm trying to figure out why I'm getting so much leading and need help!

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243winxb · April 21, 2012, 04:11 PM

Lee- "If the leading appears in the second half of the barrel, the bullet is running out of lube." Maybe coat them with some Lee Alox liquid? Drop back to 4.3 grs. Less pressure on the bullet for that alloy. Don't use a Lee Factory Crimp Die with lead.

bossman · April 23, 2012, 08:53 AM

What was your Col? Hodgdon shows a 1.10 col with their load data. If you loaded shorter, that might be the difference with the chrono numbers.

Some times working with lead will just be trial and error to find the right velocity for your gun. I would think with the 18 BHN you should be mid to max loads to expand and seal that hard a bullet.

Rangefinder · April 23, 2012, 03:58 PM

Quote:

Lee- "If the leading appears in the second half of the barrel, the bullet is running out of lube."

Under "normal" circumstances, that would be the case often enough. With the given information, I would strongly disagree. FIRST issue is fit. .356 is the right size for a jacketed bullet. Lead NEEDS to be .001 to .002 over, meaning .357 to .358 for a 9mm. He's not running out of lube in such a short barrel--he's simply not getting use of it. Without contact and a tight seal through the grooves, there is gas blow-by, making the lube that should be doing its job unable to do so. Hardness is NOT helping this issue. 18BHN is too hard for the bullet to get obturation, furthering the problem of too small of a size and not sealing the bore. I'd bet accuracy was not the greatest either.

djcantr · April 25, 2012, 09:35 AM

Quote:

What was your Col? Hodgdon shows a 1.10 col with their load data. If you loaded shorter, that might be the difference with the chrono numbers.

Some times working with lead will just be trial and error to find the right velocity for your gun. I would think with the 18 BHN you should be mid to max loads to expand and seal that hard a bullet.

I loaded to 1.10" length. I figured I'd need to load up near the max load to get the bullet to seal. With the 1,220 fps average I got, I'm not sure I should load them any hotter. Isn't that towards the top end of what 9mm Luger velocity should be?

djcantr · April 25, 2012, 09:39 AM

Quote:

Under "normal" circumstances, that would be the case often enough. With the given information, I would strongly disagree. FIRST issue is fit. .356 is the right size for a jacketed bullet. Lead NEEDS to be .001 to .002 over, meaning .357 to .358 for a 9mm. He's not running out of lube in such a short barrel--he's simply not getting use of it. Without contact and a tight seal through the grooves, there is gas blow-by, making the lube that should be doing its job unable to do so. Hardness is NOT helping this issue. 18BHN is too hard for the bullet to get obturation, furthering the problem of too small of a size and not sealing the bore. I'd bet accuracy was not the greatest either.

The hard cast bullets I've found for sale through several casters are either .355" or .356". I thought 9mm bores were .355" and .356" was the correct lead bullet to use. But I guess since I tapped a .356" bullet through the barrel and it didn't contact the grooves then mine is larger than .356"... You do measure the bore by the grooves, not the lands, correct? The lands would be a smaller diameter. I hope I'm using the proper terminology. Still learning all this stuff, obviously.

oldmanFCSA · April 25, 2012, 09:52 AM

Quote:
"Under "normal" circumstances, that would be the case often enough. With the given information, I would strongly disagree. FIRST issue is fit. .356 is the right size for a jacketed bullet. Lead NEEDS to be .001 to .002 over, meaning .357 to .358 for a 9mm. He's not running out of lube in such a short barrel--he's simply not getting use of it. Without contact and a tight seal through the grooves, there is gas blow-by, making the lube that should be doing its job unable to do so. Hardness is NOT helping this issue. 18BHN is too hard for the bullet to get obturation, furthering the problem of too small of a size and not sealing the bore. I'd bet accuracy was not the greatest either."

"The hard cast bullets I've found for sale through several casters are either .355" or .356". I thought 9mm bores were .355" and .356" was the correct lead bullet to use. But I guess since I tapped a .356" bullet through the barrel and it didn't contact the grooves then mine is larger than .356"... You do measure the bore by the grooves, not the lands, correct? The lands would be a smaller diameter. I hope I'm using the proper terminology. Still learning all this stuff, obviously. "

RangeFinder is most definitely correct. You need a larger diameter bullet to stop the blow-by, which deposits the lead vapors near the end of the barrel which is cooler than near the chamber. Once you have a good seal, leading will be reduced, velocities will increase, Standard Deviations should decrease.

Have FUN, but do it correctly. Reloading is a learning experience, I am still learning since starting to reload in 1972 as a college student at South Dakota State University.

April 21, 2012, 03:43 PM	#1
djcantr Senior Member Join Date: January 28, 2012 Posts: 215	Chrono results and leading problems I loaded up a few hundred 115 grain LRN bullets from Missouri Bullet Co. into 9mm Luger cases with a CCI SP primer and 4.5 grains of Win 231. I shot a couple hundred of them from my Arcus 98DA today. I recently bought a Chrony F1 and today was the first time I used it. I shot some of these 9mm reloads and these were the readings: 1151 1214 1218 1196 1284 1242 1205 1228 1235 I was surprised to have an average of over 1,200 fps when I was using a load in the middle of the suggested data (4.3 grains start and 4.8 grains max). I came home and cleaned the pistol. It was leaded pretty bad. I take that back... It didn't look like it was leaded all that bad but it sure was a pain to remove. Took a good half hour to scrub the barrel and I mean I was seriously scrubbing. Probably ran that brush through a couple hundred times. The leading was in the last 1/4 to 1/3 of the muzzle end of the barrel. Close to the chamber was clean as a whistle. I decided to slug the bore. Below is a picture. The bullets are sized to .356". Where the lands dug into the bullet I'm measuring .350". The grooves did not contact the bullet. The picture is a bit misleading because the sides of the slugged bullet don't look to match the un-slugged bullet but that's just because they're sitting in my hand at a slightly different angle. The bullets are 18 BHN. Should I try loading them at 4.8 grains so the base of the bullet maybe seals better in the grooves? I'm trying to figure out why I'm getting so much leading and need help! Uploaded with ImageShack.us Last edited by djcantr; April 21, 2012 at 03:48 PM.

April 23, 2012, 08:53 AM	#3
bossman Senior Member Join Date: November 16, 2010 Location: Arkansas Posts: 996	What was your Col? Hodgdon shows a 1.10 col with their load data. If you loaded shorter, that might be the difference with the chrono numbers. Some times working with lead will just be trial and error to find the right velocity for your gun. I would think with the 18 BHN you should be mid to max loads to expand and seal that hard a bullet. __________________ NRA life member When the going gets tough, I just open another beer.

April 25, 2012, 09:52 AM	#7
oldmanFCSA Senior Member Join Date: November 8, 2010 Location: WISCONSIN Posts: 283	Quote: "Under "normal" circumstances, that would be the case often enough. With the given information, I would strongly disagree. FIRST issue is fit. .356 is the right size for a jacketed bullet. Lead NEEDS to be .001 to .002 over, meaning .357 to .358 for a 9mm. He's not running out of lube in such a short barrel--he's simply not getting use of it. Without contact and a tight seal through the grooves, there is gas blow-by, making the lube that should be doing its job unable to do so. Hardness is NOT helping this issue. 18BHN is too hard for the bullet to get obturation, furthering the problem of too small of a size and not sealing the bore. I'd bet accuracy was not the greatest either." "The hard cast bullets I've found for sale through several casters are either .355" or .356". I thought 9mm bores were .355" and .356" was the correct lead bullet to use. But I guess since I tapped a .356" bullet through the barrel and it didn't contact the grooves then mine is larger than .356"... You do measure the bore by the grooves, not the lands, correct? The lands would be a smaller diameter. I hope I'm using the proper terminology. Still learning all this stuff, obviously. " RangeFinder is most definitely correct. You need a larger diameter bullet to stop the blow-by, which deposits the lead vapors near the end of the barrel which is cooler than near the chamber. Once you have a good seal, leading will be reduced, velocities will increase, Standard Deviations should decrease. Have FUN, but do it correctly. Reloading is a learning experience, I am still learning since starting to reload in 1972 as a college student at South Dakota State University. __________________ OldmanFCSA = "Oldman" at www.fcsa.org FCSA Member, SCSA Member, NRA Member, & AMA Member "Oldage & Treachery will overcome Youth & Skill"

April 21, 2012, 04:11 PM	#2
243winxb Senior Member Join Date: July 26, 2011 Location: USA Posts: 1,730	Lee- "If the leading appears in the second half of the barrel, the bullet is running out of lube." Maybe coat them with some Lee Alox liquid? Drop back to 4.3 grs. Less pressure on the bullet for that alloy. Don't use a Lee Factory Crimp Die with lead.