I'm loading up some rounds using Sierra 9390 80gr Matchking bullets. In their data book they say to seat it to an OAL of 2.550" I am using a sled so magazine is not in the picture. Thing is when I measured the(I think it's called ogive) of the round at 2.550 with the Hornady comparator gauge it came out to 2.044" but my barrel's ogive is only 1.950" so the round is way to long or would be shoved into the lands(rifling?) almost .050". How can they(Sierra) give you an OAL of 2.550 when it won't fit. Their data is in the .223(AR-15) section so it's not a measurement for a bolt action? Maybe I'm just confused but the numbers don't add up.
Data book doesn't jive with RIfle
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FYI, Hodgdon gives 2.550 as the COL for that bullet too.
How did you measure your chamber's length to the lands? If you used the Hornady tool, what bullet did you use when you did the measurement? Have you made a dummy bullet (no powder, no primer) at COL 2.550 and tried to chamber it?
IOW, are you certain your measurement of your chamber was correct?
If your measurements are correct, please describe your rifle . . . make, model, and chamber (223, 556, or Wylde) . . . and if there was any special work done on it.
How did you measure your chamber's length to the lands? If you used the Hornady tool, what bullet did you use when you did the measurement? Have you made a dummy bullet (no powder, no primer) at COL 2.550 and tried to chamber it?
IOW, are you certain your measurement of your chamber was correct?
If your measurements are correct, please describe your rifle . . . make, model, and chamber (223, 556, or Wylde) . . . and if there was any special work done on it.
I measured the chamber length with the Hornady C.O.L. tool and used the Sierra 9390T 80gr bullet then measured it with the Hornady comparator gauge. I measured it 10 times and the average came out to the 1.950" with the shortest at 1.953" and the longest at 1.958". I have not made a dummy round yet but I will. As far as rifle itself, I built it myself but the barrel is a HP MP 20" 5.56 Nato 1:7 twist.
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Shynloco
You can lead a horse to water, but ........
EXACTLY! Reloading Manuals contain general guidelines with results from THEIR weapon which they describe and name in each section. Your's may be different and I've seen it in various instances in every manufacturers manual I own.
Alex
The Hornaday gage does not measure the "Ogive". It's just a tool with a somewhat random sized hole in it and is used for comparative measurements only, so any number you come up with will be used for measuring a relative distance only.
Unless YOU measured the base to ogive of your load with that exact tool, after YOU seated the bullet to the lands in YOUR rifle, none of the numbers you come up with or read in a book have any meaning whatsoever. The tool simply allows you to confirm that you have hand loaded a particular lot of bullets to a particular jump in a consistent manner, and that is all it's good for. Of course, your brass must be consistently sized too for that jump to be consistent since the shoulder of the brass is the datum in most chambers.
Unless YOU measured the base to ogive of your load with that exact tool, after YOU seated the bullet to the lands in YOUR rifle, none of the numbers you come up with or read in a book have any meaning whatsoever. The tool simply allows you to confirm that you have hand loaded a particular lot of bullets to a particular jump in a consistent manner, and that is all it's good for. Of course, your brass must be consistently sized too for that jump to be consistent since the shoulder of the brass is the datum in most chambers.
OK guys, I have to apologize, I was looking at the wrong data I had for my bullets. I quoted an ogive max of being 1.950" which was for another brand bullet. The correct max ogive for the Sierra bullet is 2.012".
Anyway, I made a dummy load at 2.550" OAL and sure enough it stuck in the chamber. So I seated it down until it did not stick and the results were an OAL of 2.530" with a ogive of 2.030". I guess I was pretty close with my beginning measurements of the chamber itself.
Now that I know what the chamber is my next question would be how much should I decrease my powder. The max load for N140 according to the Sierra data is 23.5gr with an OAL of 2.550". Since my max OAL is 2.530" that is of course a .020" decrease.
Texas10, the brass I am using are all the same length with a L.C. headststamp. I understand the measurements you are talking about, I was just stating what I measured but maybe not used the correct wording. What I am doing is using the Hornady OAL gauge with the bullet and pushing it into the chamber until it just touches then I use the comparator gauge to measure the length from the base to where the bullet touched the lands which I thought was called the ogive.
Anyway, I made a dummy load at 2.550" OAL and sure enough it stuck in the chamber. So I seated it down until it did not stick and the results were an OAL of 2.530" with a ogive of 2.030". I guess I was pretty close with my beginning measurements of the chamber itself.
Now that I know what the chamber is my next question would be how much should I decrease my powder. The max load for N140 according to the Sierra data is 23.5gr with an OAL of 2.550". Since my max OAL is 2.530" that is of course a .020" decrease.
Texas10, the brass I am using are all the same length with a L.C. headststamp. I understand the measurements you are talking about, I was just stating what I measured but maybe not used the correct wording. What I am doing is using the Hornady OAL gauge with the bullet and pushing it into the chamber until it just touches then I use the comparator gauge to measure the length from the base to where the bullet touched the lands which I thought was called the ogive.
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OK, so you now have a good reference point to start with, 2.030 is touching lands. Proper load development, and I am a$$uming you are striving for accuracy here, is to pick a starting charge, say about midway between min and max, and develop a seating depth study. There are many ways to do that, but you might start by seating in .005 increments starting at say, .030 off and working forward. If you're shooting a gas operated gun, you might want to avoid seating INTO the lands in case you must eject a live round and end up with a bullet stuck in the barrel and propellant in your action. Just load up to touching and shoot over a chronograph watching for velocity spread (ES and SD). If you don't have a chrono, you can just watch for tightest groups. Once you've determined a best seat depth then do an OCW load workup varying charge wt. watching for signs of overpressure as you near a max load. Pick the three consecutive loads that print at about the same elevation on the target, you're middle one is the charge wt. you want. Then fine tune the seat depth again. If it still isn't shooting well, try a different primer, or different powder. The 223 will shoot just about any powder well, so you may not even make it this far before you have a good shooting load.
Write back and let us know how it goes.
Write back and let us know how it goes.
hogpatrol
Gold $$ Contributor
Loading book COALs and a buck and a quarter will get you a coffee at the quickie mart. They are almost a totally useless number. At most, they confirm your loaded round will go in a non-identified rifle's magazine. Go by your gauges and set the bullet where you want it in relation to the lands.
Yep, Looking at the Hornady book at their 80gr bullet which is longer than the Sierra bullet they have the OAL at 2.360 sitting on 2.47gr of N140.
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jds holler
Gold $$ Contributor
ALSO -- bullet ogives will vary from lot to lot by as much as .005", I am sad to say. Maybe more on ones that I haven't yet checked. 
There just isn't any substitute for checking a particular bullet with your particular chamber if you want to know where ya stand. The books OAL is a veeerrry general guide, and not to be trusted. jd
There just isn't any substitute for checking a particular bullet with your particular chamber if you want to know where ya stand. The books OAL is a veeerrry general guide, and not to be trusted. jdA couple things:
The ogive is the curved portion of the bullet. The whole thing. So using "ogive" as a reference point gets confusing.
The Hornady COAL tool is invaluable for some things. As data to be shared it's worthless because the holes in the inserts aren't precise or consistent. Your Hornady tool and mine may give very different results from the same round.
"I measured it 10 times and the average came out to the 1.950" with the shortest at 1.943" and the longest at 1.958"
If you had 15 thousandths difference in ten measurements there's a problem. The tool is capable of +/- 0.001". It usually one of two issues:
- The case isn't stopping on the shoulder as it should be. If the case is hitting the walls of the chamber all bets are off and results are random.
- You need to work on your technique. It's not as simple as it might seem. There are several ways to do it that can work as long as you do it exactly the same way every time.
One last point - To be sure you're actually off the lands you can spin the bullet in 0000 steel wool before you chamber the cartridge as it makes the rifling marks much easier to see. Your loaded round of 2.030" may be into the rifling also but just not as visible.
Sorry for interrupting.....
The ogive is the curved portion of the bullet. The whole thing. So using "ogive" as a reference point gets confusing.
The Hornady COAL tool is invaluable for some things. As data to be shared it's worthless because the holes in the inserts aren't precise or consistent. Your Hornady tool and mine may give very different results from the same round.
"I measured it 10 times and the average came out to the 1.950" with the shortest at 1.943" and the longest at 1.958"
If you had 15 thousandths difference in ten measurements there's a problem. The tool is capable of +/- 0.001". It usually one of two issues:
- The case isn't stopping on the shoulder as it should be. If the case is hitting the walls of the chamber all bets are off and results are random.
- You need to work on your technique. It's not as simple as it might seem. There are several ways to do it that can work as long as you do it exactly the same way every time.
One last point - To be sure you're actually off the lands you can spin the bullet in 0000 steel wool before you chamber the cartridge as it makes the rifling marks much easier to see. Your loaded round of 2.030" may be into the rifling also but just not as visible.
Sorry for interrupting.....
Point taken Dave, I know I need to get better at the feel of when the bullet touches and I am getting better at it, just not perfected it yet. I did make a mistake though on my number of 1.943" above, it should have been 1.953", I'll edit that.
I've also been using once fired brass and then sizing, trimming and was thinking that maybe I should use new brass instead.
What I am after is not a load that would win contests(would be nice though) but more that I can hit the 6" bullseye at the 600yd range or at least close to it.
I've also been using once fired brass and then sizing, trimming and was thinking that maybe I should use new brass instead.
What I am after is not a load that would win contests(would be nice though) but more that I can hit the 6" bullseye at the 600yd range or at least close to it.
If you have a Hornaday modified case to use with your Hornaday OAL gages, I'll share with you how I finally got it to give me a consistent reading in my BOLT gun. If you're loading an AR, I guess you can do this with the bolt and carrier out.
Run the modified brass through your FL sizing die. Seat a bullet long and screw it onto the rod. Slide this into your chamber, pushing firmly and you will feel the bullet stick in the lands as you try to withdraw it. Remove, and seat the bullet a bit deeper. Repeat until you can feel the cartridge touch home after a firm push but without sticking. If the Hornaday brass measures differently than your fire formed brass, you'll have to compensate for the different dimensions when you record the "Touching Lands" dimension in your log book. If, say, the Hornaday brass is .002 shorter at the shoulder than your FF brass, add .002 to the gage reading and use that as your "Touching Lands" dimension.
When I do this, I start by cleaning the chamber/throat free of carbon and check the fit of the modified cartridge in the chamber without a bullet. This helps to eliminate any false stickiness that might be confused with the bullet sticking in the lands.
When I went to this method of using the Hornaday tool, I looked back in my records and found I was WAY off in what I thought was my "touch" dimension. With my 223 I was jamming bullets .015 into the lands and thinking I was .010 off. I probably gave up prematurely on some bullets that needed to be jumped cause they just didn't shoot well.
Run the modified brass through your FL sizing die. Seat a bullet long and screw it onto the rod. Slide this into your chamber, pushing firmly and you will feel the bullet stick in the lands as you try to withdraw it. Remove, and seat the bullet a bit deeper. Repeat until you can feel the cartridge touch home after a firm push but without sticking. If the Hornaday brass measures differently than your fire formed brass, you'll have to compensate for the different dimensions when you record the "Touching Lands" dimension in your log book. If, say, the Hornaday brass is .002 shorter at the shoulder than your FF brass, add .002 to the gage reading and use that as your "Touching Lands" dimension.
When I do this, I start by cleaning the chamber/throat free of carbon and check the fit of the modified cartridge in the chamber without a bullet. This helps to eliminate any false stickiness that might be confused with the bullet sticking in the lands.
When I went to this method of using the Hornaday tool, I looked back in my records and found I was WAY off in what I thought was my "touch" dimension. With my 223 I was jamming bullets .015 into the lands and thinking I was .010 off. I probably gave up prematurely on some bullets that needed to be jumped cause they just didn't shoot well.
hogpatrol
Gold $$ Contributor
Check out this thread and view Alex Wheeler's method of finding the lands.
http://forum.accurateshooter.com/th...ithout-a-modified-case-for-oal-gauge.3900469/
When your Hornady gauge numbers come within .002 of Alex's method, you'll pretty much have the feel for getting good numbers with the gauge.
http://forum.accurateshooter.com/th...ithout-a-modified-case-for-oal-gauge.3900469/
When your Hornady gauge numbers come within .002 of Alex's method, you'll pretty much have the feel for getting good numbers with the gauge.
Went out to the range and tested some loads out according to my measurements and was pleased with the results of two of them. All bullets were loaded at .010" off the lands at an oal of 2.530" and using N140 for powder, L.C. brass and Rem. 7 1/2 br primers.
Load 1: 22.0gr of N140 Sierra 80gr HPBT MatchKing. Max 2536fps Min 2474fps Group size @ 100yds .371"
Load 2: 23.0gr N140 Sierra 80gr HPBT Matchking. Max 2603fps Min 2558fps Group size @ 100yrds .298"
The velocities were what I expected of being more than what the Sierra book called for since my oal was less than they had at 2.550"
Load 1: 22.0gr of N140 Sierra 80gr HPBT MatchKing. Max 2536fps Min 2474fps Group size @ 100yds .371"
Load 2: 23.0gr N140 Sierra 80gr HPBT Matchking. Max 2603fps Min 2558fps Group size @ 100yrds .298"
The velocities were what I expected of being more than what the Sierra book called for since my oal was less than they had at 2.550"
CONGRATULATIONS !!! You're well on your way to being a savvy reloader.BTW, I decided to make up my own modified case for the Hornady OAL gauge using one of my once fired L.C. cases and took 5 measurements. 3 of them were 2.019" and the other two were 2.020". I think I got it now!
Brians356
Silver $$ Contributor
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