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Projectile Ogive Measurements
- Thread starter ninosdemente
- Start date
ninosdemente
New member
Thanks guys for the help. Glad to know nothing to worry about then.
That was a new unfired brass I used. Did chamfer, perhaps need to inspect better to make sure.
If my rifling starts at 1.9805", how deep is too deep? Here is a picture of comparison of how much of the projectile is seated inside brass. Curious as jetinteriorguy mentioned his rifle started at 2.223" and now is at 2.295".
http://www.mentegraphics.com/pictures/131.jpg
That was a new unfired brass I used. Did chamfer, perhaps need to inspect better to make sure.
If my rifling starts at 1.9805", how deep is too deep? Here is a picture of comparison of how much of the projectile is seated inside brass. Curious as jetinteriorguy mentioned his rifle started at 2.223" and now is at 2.295".
http://www.mentegraphics.com/pictures/131.jpg
ninosdemente
New member
Metal god, didn't clean it from last trip which was last week. But did give it a cleaning prior to last weeks trip. Will definitely do a thorough cleaning.
A couple of things:
I don't see any of those bullets showing signs of contact with the lands. You suggest you thing your rifling may start at 1.985", but you are getting bullets in longer and still without marks, so I think that 1.985" is significantly short. If you are making the determination with the Hornady Lock N' Load OAL Gauge, one thing I have found with the match chamber on my 223 Rem course gun is that I can push the bullet into its chamber with that gauge and have it hang up on the entry to the freebore, giving me a false short reading' short enough that if it were real, some commercial ammo wouldn't chamber. The fact your bullets appear to be scuffing on that same corner tells me you may be suffering from the same thing. The way I solved it was to loosen the thumbscrew and push the bullet out beyond what the apparently false reading position was and then tightened it again. I then set the rifle muzzle-up with the toe of the buttstock on the edge of my bench and insert the gage straight up and wiggled it when the bullet started to catch and until I felt it slip in beyond that catch point. Once it was there, I kept the gage in place with one hand while I set the rifle in a cleaning cradle (laying it on the bench would be fine). I then loosened the thumbscrew again and finish seating the bullet and gage case forward and tightened the screw again and was able to get a measurement that matched my experience with it.
I note that your photos appear to my eye to show the bullet seated perhaps too far into the case. That uses up powder space, and if you use too much seating depth, it will raise the peak pressure just the same as if you seated the bullet out too close to the lands. Based on that appearance, let me suggest another approach to try. Put the bullet in the OAL gauge adapter case and adjust the sliding ram until you have the bullet makers recommended COL from the case head to the tip of the bullet and tighten the thumbscrew. Make the base-to-ogive measurement and figure any result you get that is shorter is probably due to the bullet hanging up. After all, the bullet maker uses that number in their loaded ammo for sale, so it has to be compatible with any standard chamber. Next, slide that setup into the chamber and wiggle it, if necessary, until the case slips in all the way. Then, as above, loosen the thumbscrew and push the gauge ram forward until the bullet stops firmly. Tighten it again and pull it out and measure what you have.
I don't see any of those bullets showing signs of contact with the lands. You suggest you thing your rifling may start at 1.985", but you are getting bullets in longer and still without marks, so I think that 1.985" is significantly short. If you are making the determination with the Hornady Lock N' Load OAL Gauge, one thing I have found with the match chamber on my 223 Rem course gun is that I can push the bullet into its chamber with that gauge and have it hang up on the entry to the freebore, giving me a false short reading' short enough that if it were real, some commercial ammo wouldn't chamber. The fact your bullets appear to be scuffing on that same corner tells me you may be suffering from the same thing. The way I solved it was to loosen the thumbscrew and push the bullet out beyond what the apparently false reading position was and then tightened it again. I then set the rifle muzzle-up with the toe of the buttstock on the edge of my bench and insert the gage straight up and wiggled it when the bullet started to catch and until I felt it slip in beyond that catch point. Once it was there, I kept the gage in place with one hand while I set the rifle in a cleaning cradle (laying it on the bench would be fine). I then loosened the thumbscrew again and finish seating the bullet and gage case forward and tightened the screw again and was able to get a measurement that matched my experience with it.
I note that your photos appear to my eye to show the bullet seated perhaps too far into the case. That uses up powder space, and if you use too much seating depth, it will raise the peak pressure just the same as if you seated the bullet out too close to the lands. Based on that appearance, let me suggest another approach to try. Put the bullet in the OAL gauge adapter case and adjust the sliding ram until you have the bullet makers recommended COL from the case head to the tip of the bullet and tighten the thumbscrew. Make the base-to-ogive measurement and figure any result you get that is shorter is probably due to the bullet hanging up. After all, the bullet maker uses that number in their loaded ammo for sale, so it has to be compatible with any standard chamber. Next, slide that setup into the chamber and wiggle it, if necessary, until the case slips in all the way. Then, as above, loosen the thumbscrew and push the gauge ram forward until the bullet stops firmly. Tighten it again and pull it out and measure what you have.
Looks like the ones I get when they are too far seated.
One other clue is the bolt sticks trying to pull back.
Its not all bullets due to the shape but most.
And no you won't see the rifling as you are not far enough in and thee is some variation on the lands - that is from precision target barrels by the way of which I own 3.
One other clue is the bolt sticks trying to pull back.
Its not all bullets due to the shape but most.
And no you won't see the rifling as you are not far enough in and thee is some variation on the lands - that is from precision target barrels by the way of which I own 3.
jetinteriorguy
New member
Hey Nino, do me a favor, if you ever figure out how to make the 140 RDF's shoot let me know the magic combination please. I've burned up around 500 rounds and never could do better than 1.25 MOA and most of the time at 1.5 MOA.
ninosdemente
New member
Sure will jetinteriorguy.
Thanks guys for the help. Metal god, I did give it a thorough cleaning last night and when I inserted factory ammo it did give me the same marks. Will just forget about as it didn't affect when I loaded some Hornady ELD Match 140 gr.
RC20, do you shoot the rounds you make when they are seated deep? Results?
Unclenick, will give that a try. Thanks.
Thanks guys for the help. Metal god, I did give it a thorough cleaning last night and when I inserted factory ammo it did give me the same marks. Will just forget about as it didn't affect when I loaded some Hornady ELD Match 140 gr.
RC20, do you shoot the rounds you make when they are seated deep? Results?
Unclenick, will give that a try. Thanks.