Help with bullet depth...am I touching the lands? pic included.

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AShorvath

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I am wanting to load up some rounds tonight and I can figure out if I am touching the loads or it it something else. I am 95% sure it is the lands but I am a little doubtful since my OAL is right at the spec from Barnes. They are 150gr TTSX's at a 2.861" OAL with a 2.090" case length (for 300wsm).

Do these marks make sense considering spec OAL?

Rifle is a Sako 75 Finnlight, magazine will allow 2.910" if you want to know...

DSC_3406_zpsa3030a70.jpg
 
I don't see rifling marks, but picture is not the best. Don't use the flash, or put a piece of masking tape over the flash, to calm it down.

When starting to load a new bullet, I deliberately seat the first round very long, and then chamber it. The rifling marks will be clear. I note how long they look, and then screw the seater stem in almost as much as the length of the mark.

I then seat another round and expect to see a short mark.

Then I load another round, giving the seater stem a half turn. If that round chambers and gets marked, I load another, a half turn deeper. Repeat until the round comes out with no mark.

BTW, a quarter turn on the seater stem is about 12 thou.

Then I take all the rounds with a mark on the bullet and seat them to the new deeper depth.
 
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I've used the magic marker and it works.

Somebody else has come up with a really good suggestion - take a spare sized, unprimed casing and cut down the neck with a hacksaw all the way to the shoulder. Seat the bullet quite long and chamber the round. When it pops out, you'll have the length for that bullet just touching the lands.
 
Color the entire bullet, makes it easier to see.

Seat it really long so that it does hit the lands then you will know what to look for.

I start long, to the point where the bolt won't close, once it finally closes I record that length.I keep seating the bullet deeper until I see the color just starting to come off, then that is where I say the lands are at for my reference point.It's just for myself knowing how much jam from touching to not closing , IMO the more data you have the better off you are.

Sometimes you may not see an even amount of color removed for each land but you will eventually be able to determine where you are at, just seat out a bit longer and it will show.
 
I'm new to precision shooting and reloading... and I guess shooting all together since I was a kid.

Either way, my technique may not be right, but I can't see it being THAT flawed.

1) Make a dummy round in a once fired case, or new case. Seat the bullet long. Install in action. If the bolt doesn't close relatively easily, seat the bullet deeper and use the bullet pullet to cycle the seating a few times to loosen the brass.

2) Paint the tip of the marker with your colour choice of jiffy marker.

3) Using calipers at .3 (it doesn't matter measurement) mark a circle around where the lands should hit on the bullet. Light marking is all that's needed. Then mark a common measuring point.

4) Place round in action again and gently close the bolt. Then remove it. IMPORTANT: Make sure to hold the round in while extracting and gently extract making sure not to disrupt the position of the bullet. Measure the distance from the line (where marked) to end of case.

5) Confirm with a few more tests. They should all be bang on.

6) Deduct desired distance from lands and record measurement

7) Slowly seat bullet on dummy round till dimension is met.

8) Lock down seater die (if possible)

9) Use dummy round for set-up on further reloads. Just keep the measurement above (both on and off lands) to confirm the bullet is still a good example when wanting to replicate later.


Sorry if I stated the obvious, or it's not what you wanted. Just saying what I did. My measurement was WELL above what would fit in my Rem 700 mag (if I had one), but I shoot .308 as well in a Rem 700.

Please correct me if my method is flawed. Just thought it was somewhat logical and could be done with tools you already have. I for one couldn't get reliable land marks on my bullet when loading with a markered or soot covered tip.
 
Shibby! - I had an old sergeant tell me one time that if it looks dumb but works, then it ain't dumb. Sounds like you have it pretty well wrapped. I fully agree with your suggestion about keeping dummy rounds for setting the dies for subsequent sessions - makes very good sense.
 
Re Dummy rounds. I make them too, to make setting dies real quick. When I make a dummy I clean the inside of the neck and smear some LokTite on it so the bullet stays put.

The OP was asking about finding the OAL with a new bullet.
 
Buy the hornady cases with the threaded base and the rod, push rod tight and tighten set screw with bullet of choice in place. remove, and measure the distance from base of case to the ogive (where bullet becomes same diameter as the barrel) with an adapter for a set of verniers. Then you can reload to the length that is most accurate (.010, .020 off lands) when you change the bullet. It has worked really well for me. It costs about $75 to get all the gear, but i think its worthwhile.
 
^^^This.^^^

If you're going to load for serious accuracy, an OAL gauge and a bullet comparator (which goes on your calliper) are well worth the money. Those two tools make this process fast, accurate and repeatable.

At one time I knew what odd thread Stoney Point (now Hornady) used on the OAL gauge/special case, but I forget. It was one that you'd have to order a tap for, but after that you could make your own cases for each calibre.
 
ATOM said:
Shibby! - I had an old sergeant tell me one time that if it looks dumb but works, then it ain't dumb. Sounds like you have it pretty well wrapped. I fully agree with your suggestion about keeping dummy rounds for setting the dies for subsequent sessions - makes very good sense.
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Haha.. Thanks... I think. Seems to work. Just checked some tonight using my dummy round. I know the reloads are still off the lands and that's to .005 so resetting the die using a dummy round must be pretty accurate (at least not over .005 difference). Checked probably 15 rounds. I don't like to do this at home but my "range" is 1.5 hours away. Extra caution was used and the muzzle was always pointed at a concrete wall in my basement.

muledeercrazy2 said:
Buy the hornady cases with the threaded base and the rod, push rod tight and tighten set screw with bullet of choice in place. remove, and measure the distance from base of case to the ogive (where bullet becomes same diameter as the barrel) with an adapter for a set of verniers. Then you can reload to the length that is most accurate (.010, .020 off lands) when you change the bullet. It has worked really well for me. It costs about $75 to get all the gear, but i think its worthwhile.
Click to expand...

That's why I didn't pick up the right tools. Not necessarily because of the cost (although that does come into play), but because I highly doubt I could find these tools locally. I know I looked for the ogive gauge to attached to calipers without luck. I've also had my eye open for that tool without luck. I'd hate to ask ATRS because then I'd want to buy it, but I think I have a system that works reasonably well.

For the original thread starter, both of these methods would determine if you are actually touching the lands. As mentioned I'm new, but I'm somewhat surprised that your rounds come out shorter than magazine limitations.

If you have previously fired brass laying around, slide a bullet in there and just close the bolt gently. See what happens.
 
From the pic it kinda looks like the marks could have been caused during feeding, tuff to see tho. Do the marks go all the way around or just what can be seen in the pic?
 
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