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Old January 3, 2012, 08:56 PM   #1
kmaysob
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coal issue

hey guys, so i finally started pressing bullets tonight. my coal keeps changing. im trying to get a coal of 2.800. i set it up, press one bullet, comes out perfect. press another it may be perfect might be off by 5 thousandths. i cant get a consistent 2.800. my cases are trimmed perfect, my dies are tight, my shell holder is tight, one thing i did notice is the bullets vary in length. i cant see how that could make the difference though. i even tried cleaning the dies and the shell holder. im at a loss. any help would be appreciated.
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Old January 3, 2012, 09:31 PM   #2
mrawesome22
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It is the tips varying. If you want a consistent measurement, measure from base to bullet ogive with a comparator tool.
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Old January 3, 2012, 09:41 PM   #3
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ok, so i guess atm i shouldnt be concerned? im new to rifle. ive only done 45 acp and 9mm up to this point. looks like midway has a set for 30 bucks. ill have to pick a set up next pay day when i order my bipod from them. i have tried to get them all very close to the same. tried a couple in the rifle and no problems chambering. i appreciate the feedback. i have learned something new today
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Old January 3, 2012, 09:50 PM   #4
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one more question. using the comperator, will i still measure for 2.800?
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Old January 3, 2012, 10:16 PM   #5
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Quote:
one more question. using the comperator, will i still measure for 2.800?
No.
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Old January 3, 2012, 11:13 PM   #6
dacaur
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You will never get a consistent measurement from base to tip because the seating die seats the bullet by pushing on the the ogive, not the tip... I just go for an average of 2.800, adjusting the die will just have you chasing it up and down.... I set my die so they average 2.800, then sort them into groups of the same length to shoot....
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Old January 3, 2012, 11:43 PM   #7
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http://thefiringline.com/forums/show...hlight=hacksaw

Quote:
one more question. using the comperator, will i still measure for 2.800?
No. Use the hacksaw info in the link, except instead of measuring to the tip, you will be using the measurements from the comparator.

EDIT: You will have to do this with each different brand and type of bullet you use. In other words, the ogive of a vmax and the ogive of a hornady match bullet are not in the same place.

It is also advisable to make a dummy cartridge (no primer, no powder) loaded with a bullet seated where you want it. That way, if you change bullets, you can go back to the setting you want very quickly by taking the dummy round and lowing the seating stem until it touches the bullet on the dummy round.

Last edited by mrawesome22; January 3, 2012 at 11:49 PM.
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Old January 4, 2012, 12:27 AM   #8
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Quote:
You will never get a consistent measurement from base to tip because the seating die seats the bullet by pushing on the the ogive, not the tip... I just go for an average of 2.800, adjusting the die will just have you chasing it up and down.... I set my die so they average 2.800, then sort them into groups of the same length to shoot....
Well said, I also do this I use hornadys overall length gauge with the metered special case.... then I premeasure at least 30 of the lot and take the average of the "non perfect projectiles" and use the measurement of those which are the of the bunch and seat all of my rounds with that measurement but as stated above what I strive for perfection in length (depending on the particular bullet I use and the quailty of the projectile most even are right on the money. SERRIA AND BARNES are better than the average)

I also group them in those where alittle more is required to allow none to exceeded the desired COAL... then I ajust the die depth to seat more but I will not cycle the press to full down stroke but bump press the die to to meet my desired COAL. Yes its alot more work this way but it is what I strive for in my accuracy when the rubber meets the road.

This may not be for you but it is my way and I am always pleased with the reloads at the end of a long distance shooting trip.
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Old January 4, 2012, 12:43 AM   #9
kmaysob
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so would i be wasting my time with the comperators? or should i just buy a seperate crimping die and adjust constantly? ive been seriously considering buying a micrometer style die for seating and just using the regular rcbs to put a slight crimp on
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Old January 4, 2012, 01:07 AM   #10
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well, with my method of not worrying about it, MOA groups are the norm out of my savage edge, with my best groups under 1/2" at 100 yards... If you want to get really technical, thats up to you, and what kind of precision you desire... Getting 1/2" groups out of a budget hunting rifle is good enough for me.....
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Old January 4, 2012, 08:38 AM   #11
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I'd get a comparator if I were you. Someday without one you might end up seating a bullet right into the lands and not know it until the high pressure reveals itself. On two occasions I've had Hornady bullets change design of the bullet, placing the cannelure in a different position. The code number on the box (e.g., #2740) was the same. If you seat and expect the cannelure to line up with the case mouth, you will change the relationship to the lands and probably have a high pressure situation. But by seating the bullet using the comparator and measuring from the ogive to the base of the case, every bullet is the same distance from the lands, and you will recognize how the bullet style changed., which may result in a change in accuracy if you load them without a comparator. Some bullets do not have a cannelure and you'd never pick up on a manufacturing change like I described. Therefore you'd continue to use your same seating measurement, the accuracy of that load changes and you'll drive yourself nuts trying to figure out why.
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Old January 4, 2012, 08:56 AM   #12
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I think perhaps you are worrying about a non-problem.

Unless you are doing benchrest shooting, and are looking for that final "thousandth" in group size.

I've been loading rifles for about 40 years, and have never used a comparator. It would be a nice tool to have, but is certainly not necessary.
I usually try to seat the bullet to within a few thousandths of the lands, by marking a bullet with a marks-a-lot, then chambering, looking for marks from the lands. When the marks appear, I back off a tad, and call it good.
If my dies didn't seat the bullet to pretty much the same depth each time, I'd throw them out. Or get another press.
As stated before, the critical dimension is from the base of the case to the ogive of the bullet. What sticks out past the ogive is not critical, unless it is too long for your magazine.
If the bullet is seated consistently to the same depth at the ogive, and I had large differences in the bullet shape/length ahead of the ogive, I'd buy different bullets.
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Old January 4, 2012, 09:53 AM   #13
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Slightly varying OAL means nothing of itself, a rifle couldn't care less where a bullet meplat hangs in space. And it's not due to the press, dies or shell holder. It's (1) because of slightly varying ogives and (2) operator error. We live with the first, we can fix the second by paying attention to our consistancy of operation.

What does matter to accuracy is how far the bullet must travel before hitting the rifling - jump - and even that has a limited range that won't matter on target. Most factory rifles and common bullets do best with an ogive jump of 20 to 50 thou, some less and some much more, and the tolerance range is typically 10 thou or so. Anything that stays inside the good OAL range will be fine but IF we load on the ragged edge of the good range anything varying outside the tolerable range will produce "flyers".
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Old January 4, 2012, 11:04 AM   #14
kmaysob
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Dies are brand new rcbs and the bullets are sierra 168g hpbt
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Old January 9, 2012, 01:41 AM   #15
kmaysob
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took my loads out and tried them this last weekend. was quite happy with them, i do plan to buy the comperators and play with the distance to the rifling.
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Old January 23, 2012, 09:40 PM   #16
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ok, im confused. i bought the comperators and they tell me absolutely nothing. still have different measurements. even checked the bullets themselfs and i see a variance. am i just worrying about a non issue? if you see as much as .0010 difference between bullets even measuring off the ogive, how would one properly decide how far off the rifling they should be?
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Old January 23, 2012, 10:26 PM   #17
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Quote:
ok, im confused. i bought the comperators and they tell me absolutely nothing. still have different measurements. even checked the bullets themselfs and i see a variance. am i just worrying about a non issue? if you see as much as .0010 difference between bullets even measuring off the ogive, how would one properly decide how far off the rifling they should be?
Now, you know just how inperfect they are and with your comperator you can make them all the same off of the ogive. As to your COAL the easiest method would be is to buy the hornady COAL gauge and special metered brass casing which will allow you the accurate easiest reading to measurement as you push the bullet to the lands now then if this is more than you want to do normal calipers measurement will be the norm of the day.
I enjoy the most I can get from my reloads this makes me happy.
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Old January 23, 2012, 10:35 PM   #18
dacaur
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I think you are worried about a non-issue. The question is, is that .001 difference you are measuring making any difference at all when you shoot it? IMO, doubtfull.
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Old January 24, 2012, 01:38 AM   #19
mrawesome22
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A thousandth is just you pushing too hard. Or a very slight bullet imperfection. A nominal human hair is 30 thousands of an inch wide.

You have to develope the machinist's touch.
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Old January 24, 2012, 02:30 AM   #20
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How do you measure to the ogive? Doesn't the ogive vary in diameter from the OD of the bullet to near zero? Unless your comparator measured from the same diameter point as the seating plug it seems you'd still be chasing bullet variance.

Or is there an accepted standard ogive diameter for each caliber?
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Old January 24, 2012, 04:44 AM   #21
HiBC
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The reason I load 7.62/.308 to 2.800 is so they fit in a magazine.That is the coal priority.For me,I have not had an issue with the ogive engaging rifling when loading 168's to 2.800.

So,the driving criteria is fitting in the magazine.

I do agree,the seater stem engages the ogive,and a small amount of variation at the meplat is normal,and will confuse your measurment.You can hit your 2.800 for the mag,and check with a comparator on the ogive for uniformity.The number is insignificant,its variation you are looking for.

However,one sneaky long shot could be playing with you.

A typical seater die has a crimp function built in.

It is not uncommon for folks to believe it is good to bump the die on the shellholder.

If you do,you are cranking in crimp.Not to condemn crimp,but unintentional ,uncontrolled crimp caused by bumping the seater die on the shellholder causes all sorts of problems.You may stick rounds in the chamber,due to a collapsed shoulder.

If you are not doing that,great!If you are,I'd back the seater up some.You migt try putting a sized case in the shellholder,running the ram up,then screwing the die down till it contacts the case,and back it off a quarter turn.

Oh,and someone said a human hair is .030. Not so!!A fine,blonde hair might run around .0018 to .0021,whereas a red hair might run .0028 to .00315,unless it is curly,then it will have an eliptical cross section.:-)

Last edited by HiBC; January 24, 2012 at 04:49 AM.
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Old January 30, 2012, 12:59 AM   #22
kmaysob
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ok, couple more questions, i picked up some hornaday 168g hpbt bullets tonight, i dont have the hornaday loading info.
i looked at the generic info in my lyman book and it said seat to 2.775. my sierra book(for sierra bullets) has me seat my match kings to 2.800. comparing bullets side by side with a caliper, they are very very close from the ogive , to the bullet base.
base to tip they are very different. i chose, to load them to the same seating depth as the sierras beings when pressed in a case, they measure the same off the base of the case to the ogive.

i tried the method posted above of splitting a case and using it as a over all length gauge. when measured with a comperator, i get 2.324~ . when i measure my loaded rounds i get a measurement of 2.224. i must be doing something wrong.

hoping someone can shine some light on this for me
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Old January 30, 2012, 07:46 PM   #23
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bump
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Old January 30, 2012, 10:29 PM   #24
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2.8" is the correct length, according to the hornady manual #8.... not sure about the other thing....
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Old January 30, 2012, 11:57 PM   #25
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You will get the readings according to the book if you use a digital type caliper, and put the compartator on and push the caliper to zero then you will have true readings because when you put on the compartator on you lose some length you think but it really adds length just try to chamber one of those rounds you made it won't fit if you don't have digital mike then make one of you rounds the normal way and measure with out the compartator then once you have one made put on the compartator back on then measure it again then once you have that measurement leave it alone and repeat another round but NOW you have the measurement with the compartator.... I know it sounds trouble some but it is not once you got your measurement you will alway have it from this point on and can use the compartator for the same exact ogive measurement to the rifling....
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