Hornady OAL guage value
- Thread starter rimfiremac
- Start date
Excellent investment: you just measure that COAL with a bullet touching the lands, repeat 3 -4 times to make sure that the measurement is correct.
Then you can try different COAL (often max COAL - 0.010" work very well).
My Remington 700 243 Win rifle's throat was eroded by 0.130"+ after 1500 rounds fired.
Alex
Then you can try different COAL (often max COAL - 0.010" work very well).
My Remington 700 243 Win rifle's throat was eroded by 0.130"+ after 1500 rounds fired.
Alex
Chasing the lands isnt the real value of this tool "per'se.
This guage gives a shooter a reference point of bullet ogive to rifling engagement. With a given bullet.
The more measurements you have, the better you can track changes.
As you stated, it can allow you to chase throat erosion. It helps a shooter to find the ratio at which a given bullet will shoot the best in "that" barrel.
And it can also allow a shooter to adjust thier seating depth if a "new" batch of bullets has a slightly different ogive than the previous box of bullets. A single bullet design can vary box to box. Each bullet swedging press at the factory has tolerances that can be significantly different.
If the factory mixes the bullets from multiple presses, you will get a hodge-podge mixture. For most situations this is moot. Until you are looking for sub MOA performance at long distance, or sub .5MOA benchrest groups.
A good thing is that some manufacturers group the bullets of a single press into single boxes. This way all the bullets in each box will be consistant, relative to each other.
Also, you can measure just each bullet without the case, to check the individual ogive consistancy.
There are probably more than a few more reasons to use this gauge system, but these are my main points of use.
Hope this info helps in some way.
Straight shoot'in and keep it fun!
This guage gives a shooter a reference point of bullet ogive to rifling engagement. With a given bullet.
The more measurements you have, the better you can track changes.
As you stated, it can allow you to chase throat erosion. It helps a shooter to find the ratio at which a given bullet will shoot the best in "that" barrel.
And it can also allow a shooter to adjust thier seating depth if a "new" batch of bullets has a slightly different ogive than the previous box of bullets. A single bullet design can vary box to box. Each bullet swedging press at the factory has tolerances that can be significantly different.
If the factory mixes the bullets from multiple presses, you will get a hodge-podge mixture. For most situations this is moot. Until you are looking for sub MOA performance at long distance, or sub .5MOA benchrest groups.
A good thing is that some manufacturers group the bullets of a single press into single boxes. This way all the bullets in each box will be consistant, relative to each other.
Also, you can measure just each bullet without the case, to check the individual ogive consistancy.
There are probably more than a few more reasons to use this gauge system, but these are my main points of use.
Hope this info helps in some way.
Straight shoot'in and keep it fun!
I tried using the comparator but it's been an "Epic Fail": comparing a 6mm 80gr Ballistic Tip to a 6mm 105 A-Max is like comparing apples and oranges.
I expected to obtain some useful information using the bullet comparator but it's not working up to now(I might be unlucky or might not be using the comparator properly).
I have not quit on the comparator yet.
Alex
I use my stoney point comparator in conjunction with the over all length guage. The guage takes the overall length to the rifling for a given bullet. And the comparator measures the distance from the case head to the bullet ogive.
This gives a much more repeatable measurement.
I typically will measure 5-10 bullets with the overall length guage, and compare with the comparator. Take the average measurement, and mark it in my load data.
This basically creates a benchmark for that brand/weight/style of bullet.
Then I back off that measurement as I work up a load.
This gives a much more repeatable measurement.
I typically will measure 5-10 bullets with the overall length guage, and compare with the comparator. Take the average measurement, and mark it in my load data.
This basically creates a benchmark for that brand/weight/style of bullet.
Then I back off that measurement as I work up a load.
The angle I'm trying to wrap my head around about the ogive is sort of like this-
Given that bullets are uniform in form within lots, and may be different in form from lot to lot, wouldn't it hold that given an average of OAL measurements based on OAL's measured using the tool, loading live rounds to that average OAL (minus the desired jump) would provide an identical jump to the lands over that lot of live rounds? Granted that the next lot of bullets would need a slightly different OAL length to provide for the same jump via a re-measure with the tool, but it sounds like that needs to be done lot to lot anyways. It would just sound to me that measuring rounds within a lot with a comparitor to set the jump could be done using the OAL independently, otherwise it is implied that the ogive varies within each lot, making the whole notion of precision much more voodoo than it already is.
Given that bullets are uniform in form within lots, and may be different in form from lot to lot, wouldn't it hold that given an average of OAL measurements based on OAL's measured using the tool, loading live rounds to that average OAL (minus the desired jump) would provide an identical jump to the lands over that lot of live rounds? Granted that the next lot of bullets would need a slightly different OAL length to provide for the same jump via a re-measure with the tool, but it sounds like that needs to be done lot to lot anyways. It would just sound to me that measuring rounds within a lot with a comparitor to set the jump could be done using the OAL independently, otherwise it is implied that the ogive varies within each lot, making the whole notion of precision much more voodoo than it already is.
Of course they are going to be like comparing apples to oranges......even changing the lot # of the EXACT SAME BULLET TYPE will net you different readings.
This is why you want to use one, so that if/when you change bullet type or lot, you can then make a dummy round for your "at the lands" measurement of that type AND lot of bullets, and use the comparator to make sure your loaded rounds are in/onto/off the lands as much or as little as you require.
Rod B
CGN Ultra frequent flyer
I bought the Stoney Point gauge about 12 years ago. I use it measure the distance fom the bullet ogive to the leade of the rifling.
I also use the OAL guage with the appropriate inserts to get an accurate cartridge OAL. I was amazed by how much variance there was in measuring from the tip of the bullet, I believe this is due to manufacturers tolerances in OAL bullet length. Measuring from the bullet ogive is far more accurate.
I also use the OAL guage with the appropriate inserts to get an accurate cartridge OAL. I was amazed by how much variance there was in measuring from the tip of the bullet, I believe this is due to manufacturers tolerances in OAL bullet length. Measuring from the bullet ogive is far more accurate.
Rod B
CGN Ultra frequent flyer
Yes, I have found variations in length within the same box of bullets.
redshooter
CGN Ultra frequent flyer
- Location
- Central Ontario
Big Time! It makes me crazy! The last time I saw a Hornady rep I gave him a polite earful. I typically find 2-3 different lengths. If you don't use the comparator your only getting it right some of the time.
As others have stated it's a great tool. Stop by Crappie Tire and grab a dowl to pop the bullet out of the lands.
Republic of Alberta
CGN Ultra frequent flyer
- Location
- ,location, location
I just use a dry erase marker (the kind for white boards) and colour the bullet then take a piece of fired brass and dent the neck in a bit so it holds the bullet. Insert the dummy round into the rifle and close the bolt. Open the bolt and remove the dummy. Some times the bullet seats its self perfectly in the case. Other times the bullet sticks in the lands and pulls out of the case a bit so you just look at the scrape marks on the dry erase marker and re insert the bullet up to the mark. Some times the bullet sticks in the lands and you have to pop it out with a cleaning rod then insert it into the case up to the scrape marks and measure. It's free and works better than nothing.
Ah ha, now I see the value of a comparator as well.
I've tried the 'dry erase marker' technique in various forms as well, and I have little confidence in it. Lets try to avoid expanding on such methods.
Thanks fellas- been a lot of really useful info here.
I've tried the 'dry erase marker' technique in various forms as well, and I have little confidence in it. Lets try to avoid expanding on such methods.
Thanks fellas- been a lot of really useful info here.
I've done the dummy round method and the dowel down the muzzle measuring to the bolt face and then inserting a bullet into the chamber and lightly holding it in with a pencil and putting the dowel back down the barrel and measuring the difference from the bolt face mark. I think buying a tool might be the easiest method.
