Bullet Seating Depth - How to know?

IAHNTR

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I know there are a few on here that reload, so I figure someone can give me some advice on this matter. I am reloading for a Rem 700 .243. What do I need to know to seat the bullets at the correct depth in the brass? I currently have Hornady 58 grain V-Max bullets that I'm reloading, but am guessing that the same procedures will work with any bullet weight/length. Do I just seat them to the specs that are in the loading book and that came with the dies? Or do I seat one a little long, chamber it and it will seat itself and then that's what you want for OAL minus 0.005 or something like that. Maybe I'm not even on the right track. I am using Lee dies for this by the way.
--- Thanks
 

philw

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There are a number of ways to measure OAL to the lands but for me this tool is the easiest:

http://www.hornady.com/store/OAL-Gauges/

You use the tool with a dummy case for each different cartridge. The dummy case is threaded to fit on the tool, and the bullet will slide in and out of the case mouth. It's easier to use than to describe how it works.

In lots of factory rifles, the magazine box length is the limiting factor, i.e. if you seat the bullets out as far as the mag box will allow, you still won't reach the lands. An easy way to check that is to seat a bullet just under mag. length, color the bearing surface black with a sharpie, and chamber the round. If you have a rifle with a three-position safety, do this with the safety in the middle position and it's easier to feel the bullet contacting the lands when you close the bolt. If you're touching the lands with the bullet, you'll feel it (if the bullet is jammed far enough into the lands you may not be able to close the bolt) and you'll see marks on the bullet from the lands. In that case just seat it progressively deeper until it's no longer touching.

If you're not touching the lands then you're done, because you can't seat the bullets out any closer. In that case you may want to check into a custom mag. box that will allow you more room.
 

Shrek

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Thats a short bullet and Remingtons have long throats so you are not going to reach the lands. I would seat the bullet so that the base is about .1 into the case below the neck for 5 then make 5 more .1 further out and so on until you get the base a third up the neck. Then go shoot them and see if one group performs better. Take the best group and work increments of .002 up and down from your best group. I'm pretty sure you will run out of magazine lenght wth any bullet before you find the lands in a factory remington. Short bullets will run out of neck. As I'm always shooting long for caliber bullets I never have to worry about keeping enough bullet in the neck so I don't really know what the minimum bearing surface is. I'm pretty sure that a third of the neck on the bullet will hold fine.
 

Matt Cashell

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I love my Hornady OAL gauge. Easy to use and sufficiently precise. If your neck is long (and probably is), you can have the barrel rechambered deeper. You will give up a small amount of barrel length, but then can seat off the lands precisely without having to buy a barrel.
 

HellsCanyon

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Every gun is different. I don't care if a bullet is "designed" to be shot .005" off the lands or not. You need to tune your loads to your chamber. Load up 4 rounds of ammo for 5 different seating depths all .005" in variance. I say 4 rounds because I like to allow myself a "flyer" when shooting for groups and load development. You'll soon see what your rifle likes...

Mike
 

Shrek

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I love my Hornady OAL gauge. Easy to use and sufficiently precise. If your neck is long (and probably is), you can have the barrel rechambered deeper. You will give up a small amount of barrel length, but then can seat off the lands precisely without having to buy a barrel.

The hornady gage is a good investment. I put a wyatt extended magazine in my Remington 700 and I don't like it. I've had feeding problems since I put it in. I would find a jump the rifle and bullet like and shoot it until you are ready to put a new barrel on. If I'm paying the labor to rechamber a berrel I'm just going the rest of the way and putting a quality barrel back on.
 

Whisky

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Dave, if you're interested I can out you in contact with ky gunsmith and he can at least advise you on how to fix your Wyatts problem. I had one out in mine and it had to take a couple trips back to the smith due to feeding issues. He worked on it all ray and finally called Wyatts and git it figured out. Now he can install one in short order, with no issues.
 

Whisky

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Holy crap, apologize for smelling, can't type for crap on phones
 

Shrek

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Mike , .005 is great when you start at the lands but he is starting and finishing nowhere near the lands . He is starting with no reference point other than case neck. I'm think he needs to start with big jumps then tune down to small increments. What's your plan with no way to work off the lands. He doesn't have a oal gage and is going to run out of neck before he can touch the lands with a 6mm 58gr bullet.
 

Whisky

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Starting at book and working out from there has worked well for me in factory Rems. You'll be surprised, bullets can and do shoot well with lots of jump.
 
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IAHNTR

IAHNTR

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OK - I just checked some factory rounds I have and measured their Overall Length (OAL).

55 grain V-Max --- 2.586"
100 grain -------- 2.647"

Max OAL according to Lee spec sheet is 2.710"

Where should I start? I don't think I can get the OAL as long as the 100 grainers because the 58 grainers are a shorter bullet.
 

Shrek

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Whisky , I saw a scissor follower spring that I'm going to track down. As I push the round forward the base goes down and the bullet goes up and catches the back of the barrel. I may call wyatts and see what they say about it.
 

Shrek

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2.78 to 2.80 is about as long as you can get in a 700 magazine. You can start there and work back in .001 increments or as long as it will seat out with a short bullet. How full is the case with the powder charge you are using ? I would seat the bullet down to the powder and work up myself. Most powders work best without empty case. There will be several nodes where the jump works well and the one with the least empty case will give the most consistent velocity spread and most likely the most consistent accuracy.
 

Whisky

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Exactly the problem I had. Smith had to move the feed lips back a bit and all was good!
 

Shrek

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I'm not going to work the feed lips now as I can't put metal back and I plan to tear it apart and make a 6.5 saum out of it. I have a 7mm wsm coming next week I will be working on so the Remington 7-08 will have to wait.
 

HellsCanyon

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Mike , .005 is great when you start at the lands but he is starting and finishing nowhere near the lands . He is starting with no reference point other than case neck. I'm think he needs to start with big jumps then tune down to small increments. What's your plan with no way to work off the lands. He doesn't have a oal gage and is going to run out of neck before he can touch the lands with a 6mm 58gr bullet.

I was just using .005" as an example. If he can't reach the lands like you say, seat them out as far as possible while still allowing them to fit in the factory mag and then run a few test loads with .005", .010", .015"...etc more jump to see if the gun shoots better with them seated a little deeper in the case. Accuracy is also affected by the turbulence point of the powder charge contacting the bullet inside the case and you really never know if you're rifle has a sweet spot with them seated deeper than max COAL or not unless you try it. Can't hurt is all I'm saying...

Mike
 
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IAHNTR

IAHNTR

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So, I'll start by seating them to get the same overall length as the factory Hornady 55 grainers I have. I'll seat 12 at that depth (3, 4 shot groups) then go down .005 and do 12 and go up and do 12 and see what the results are.
 

Shrek

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What powder and amount. You might get some load help specific to the powder and bullet from accurateshooter website.
 

Whisky

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I wouldnt go down in depth from factory, just up. Go up in 10-15 thou increments until you hit mag box length. I bet you will have found an optimal seating depth by then.

Have you got your powder charge figured out already? Best to get that squared away before playing with depth IMO.
 

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