Seating depth

comtnman

New member
I am some what new to reloading and don't understand seating depth. I am working on some 223 50gr v-max loads. Hornady book says 2.220col. If I seat a 50 vmax in an empty case long, close the bolt then extract the col is 2.357. Would this be tight to the lands? 2.200-2.357 is a big difference, were should I be seating? How much of the bullet should be in the case? I know I can very the seat depth but not sure how much. This is a newer ruger M77 Hawkeye.Thanks for any help.
 
If your new to reloading, I suggest you go by the book. You can adjust things down the road but you need to understand what your doing and what the results may be.
No disrespect intended. Safety first, accuracy second.
 
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I wouldn't trust any measurement to the lands without the proper tools IMO. No harm in trying the book first. I think most guys go with leaving at least one bullet diameter in the case mouth as max but that's assuming a long leade.
 
Almost all firearm and ammunition or component makers(in the USA) are signatory to SAAMI specifications...Sporting Arms and Ammunition Manufacturers Institute...and almost all ammunition has cartridge overall length specs.

To keep away from Lawyer trouble, ammo and firearm makers AND reloading manuals keep what they sell fitting within those SAAMI specs. But if you look very close in most manuals, EACH bullet has a OAL associated with it.

I have a 17 Rem and shoot the 20gr VM's in it...the Hodgdon 2006 reloading manual calls for a OAL of 2.15"...my Shilen barreled 700 rechambered with a PT&G reamer won't shoot for doodly at that OAL...I have to seat that bullet out to 2.21" which gives a 0.160" "grip" to keep the nice bughole groups...my 375 H&H Savage with Horn 270 SP's seated out to max magazine capacity at 3.55" has a 0.552" grip...BUT...to get max case volume with the base of the bullet even with the base of the neck, a distance of 0.350", less than one caliber, I need to seat the bullet to 3.75" OAL and at that length it still doesn't touch the lands...I just single load the first round at 3.75" up the pipe and stuff the next three at 3.55" in the mag. I gain about 6-7 gr H20 more capacity with the longer round and about 50-75 fs more velocity which translates to an additional 175-250 ft lbs of energy. The additional extra energy on the first shot could mean the difference of the animal dying instantly or dying a little slower.

As a newbee I recommend keeping your ammo fitting those specs...as you get more familiar with the sport you will learn the ins and outs of bullet seating.

One caliber seat is good...but you will learn there is many variations on that theme, the same as variations on crimping, seating out to "touch the lands", pressure/velocity and all the rest.

Part of "the neck grip" is to keep bullets from being pushed back into the case due to banging against magazine walls or in tubular magazines...but in a single shot all that is required is enough grip to keep the bullet from being moved due to handling. Some even seat the bullet well out, use a light grip...0.001" or less neck squeeze and let the lands push the bullet back when closing the bolt.

Each caliber seems to prefer a specific "to the lands" jump, but this isn't cast in stone...and many cartridges have a prefered jump...I use 0.025" for 22 cal, 0.015" for 6mm and 0.010" to touching for 7mm and up for all new rifles I build as a starting point for load development. Sometimes it works, sometimes the rifle has other ideas.

Finding what seating depth your rifle likes for a specific bullet is part of the crap shoot of reloading.

I always recommend 6mmBR, Saubier and various Varminting forums for new comers and doing online searches. There is tons of information out there to be gleaned on ALL aspects of reloading.

Luck
 
Originally Posted By: 405 winIf your new to reloading, I suggest you go by the book. You can adjust things down the road but you need to understand what your doing and what the results may be.
No disrespect intended. Safety first, accuracy second.

Yup an the other thing is if you are have a magazine and want to use it you cannot go longer than the mag will fit.

I do think that more reading needs to be done. I understand that you are asking here to get answers as well as all of us have done. But I do think that some info has been left out for anyone to fully answer your question.

If you are shooting just one round at a time or happen to have a single shot there.

If you are using an AR rifle with factory magazines you cannot really go much further than 2.260.

Not only that I would not trust using the land method that you described. You are crushing the jacket just a bit if you are depending on closing the bolt and using the lands to determine your length. From everything I understand that is not a good way to do it.
 
You should start at .010 off the lands. You can adjust in or out from there to find the distance your rifle likes for a particular bullet. I have a 6BR that likes Hornady 105's .010 off the lands and Berger 105's .020 into (jammed) into the lands. Each bullet is different. If you start .010 off, you will usually be happy with the results. As far as C.O.L. goes, Just make sure it fits in the magazine of your rifle. As someone mentioned in a different subject post, open your calipers to .010 and see just how long that is.
 
Thanks for all the info guys. The biggist reason I want to change the depth is because I am not getting great groups. Thought I would play with this next. I have been loading for a year so I am not totaly new, but would like tighter groups. So much for saving money reloading, I just shoot more now.
 
I want to throw a twist to this thread. Do you find what load your rifle likes and then take that load and start playing with seating depth? I have read both ways some start with seating depth and some start with finding the best load for a powder and bullet and then very the seating depth.
 
Basically I start with the bullet off the lands by the amount that is known to work for that caliber AND depends on what type of action, bolt, semi-auto, singleshot. 22 cal, 0.025", 6mm, 0.020 - 0.015", 6.5 -7mm 0.015-0.010"...Larger calibers seem to like it up close and personal with the lands so seating at or into the lands is the way to go and you only have to work on the powder amount....or pick what you like, the rifle will tell you quickly what it like.

I start with 2-3 known powders for the cartridge, bullets, and ONE brand of primers that are known to be accurate...do a search, accurate load data is all over the place, but check with a reloading manual for confirmation the load is safe...FIRST.

I've been doing this same procedure for well over 40 years and it always works and usually relatively quickly. Some people call it the "ladder method", but it's nothing new. The same method has been used since the early 50's or before.

I fire 3 round groups first. MEASURE the groups accurately and write down the data on the target. Change ONE parameter at a time either powder or bullet seat...223 cases - two tenths grain, 308 size - 5 tenths, '06 - 7 tenths, belted mag 1 grain...up and down from your first group or 0.005" up and down for all sizes . The groups will either get larger or smaller...do an additional 2 tenths of powder or 0.005" seat depending on the direction. Once you have established which way to go then you can change both the powder amount and the seating about at the same time...say up a few tenths and out a few thou then fire a group. Nothing is locked.

The better the tune and the more accurate the rifle is to begin with the quicker you can hit a good load.

Usually but not always, the most accurate loads are near the top end of the pressure spectrum and pretty close to what the load manuals list for their specific bullets.

This is for a TUNED rifle...it doesn't work for krap if the barrel touches the stock at various points or the scope is not secure, or the receiver is not bedded well.

I use Fed Gold Metal primers or CCI BR primers for almost all my calibers and magnum primers for large cases. I like Hornady VM's for varmints but I use what the rifle likes and work up a load for Nosler, Sierra, Speer, etc just in case one happens to shoot better or the supply runs out.

I always use a bullet comparator of some kind, a Sinclair bullet seating measuring tool to measure what the OAL of a seated bullet is touching the lands...THEN decide what seat I want to start with.

Check out other forums, this subject has been covered time and time again so you can get lots of good information by digging around.

And your RIGHT...I NEVER saved ANY money reloading...and I guarantee if I had spent all the money I spent on reloading and all the rest of the "stuff", I would be driving a much nicer/newer truck and living in a much nicer home, AND not wake up at night thinking of ANOTHER rifle to build. Hahahahaha

Luck
 
Originally Posted By: MGYSGTYou should start at .010 off the lands. You can adjust in or out from there to find the distance your rifle likes for a particular bullet. I have a 6BR that likes Hornady 105's .010 off the lands and Berger 105's .020 into (jammed) into the lands. Each bullet is different. If you start .010 off, you will usually be happy with the results. As far as C.O.L. goes, Just make sure it fits in the magazine of your rifle. As someone mentioned in a different subject post, open your calipers to .010 and see just how long that is.

+1

That is darn good information and right on the money!

Seating one caliber into the neck is ill informed.

www.6br.com
www.benchrestcentral.com
www.saubier.com

Very experienced hunters and reloaders on these sites that give advanced reloading advise.

www.sinclairintl.com sells two tools to measure bullet seating depth off the ogive,a Stony point tool(now Hornady) and a Davidson ogive gage used in conjunction with a split neck case. I use the davidson because they are $12 per caliber and they work in establishing seating depth to the .001.

If you are interested in shooting consistant sub 1/2" groups, learing how to accurately measure your OAL in relation to how far you are off the lands is critical, and is nothing more than advanced reloading techniques....really simple stuff. MGYSGT's advise is really about as good as it gets.


Good luck!
 
In case someone is following along I would point out that I would NEVER seat a bullet "diameter deep" if that meant deeper than the published OAL in a reloading manual.

With that out of the way, a previous post has offered that if you are loading for the AR15 you can't go longer than 2.260 without single loading by hand. Of course if you're loading for a bolt rifle then disregard...

I used the method you described at first (seating a bullet in a case sized to just barely hold the case and closing the bolt). I did it for all my rifles and all my bullets one day - okay I was bored.

I've since gone out and bought the Stoney Point gauge. It's very easy but the numbers were identical.

Now if closing the bolt on your test round leaves anything other than barely perceptible marks then the number would be quite suspect. Others on this forum use a sharpie or lamp blacking to witness the marks. I just used good light and glasses.
 
Originally Posted By: MGYSGT .020 into (jammed) into the lands.

I've often wondered about the logic of loading bullets "into the lands". It would seem to me that you could seat a bullet from .02-.1 longer than the length to lands and it will be shoved back to the same seating depth when chambered, somewhere slighty pushed into the lands. I would think the only way you would achieve pushing your bullet into the lands beyond a slight amount would be to have excessive neck tension on your bullet which in itself is not inherent to accuracy. Additionaly the rate that you run your action would affect your resulting depth into the lands, so you would be introducing another variable into the process.

I know many people swear by it, and many are shooting competively, but it just simply doesn't add up on paper. Since the rifles I shoot are used in hunting situations I don't seat into the lands so I guess it's a mute point for me.
 
Seating into the lands is another way to achieve maximum accuracy and the load is worked up carefully usually in a very finely tuned benchrest rifle...BUT...it is also a way to center a round in the chamber so it starts out straighter/more centered so to speak.

Many factory chambers are sloppy beyond imagination. I've found that seating into the lands can help a lousy chambered rifle shoot much better, BUT, you have to work the load up slowly because of the pressure spike associated with the bullet being stuck into the lands.

I've also found factory chambers that were "short" and a loaded, ejected round showed land engraving on the bullet which meant it was shoved into the lands a certain amount. A lot of this might be happenen and no one has noticed or was not concerned about it if they DID see it.

For "normal" factory rifles and hunting I WOULDN'T stuff a bullet up the snout hard for a lot of reasons, but 0.020" isn't very much..you can hardly see that amount of engraving on a bullet. Check it out with a pair of calipers or mic.

Some people DO seat their bullets long and let the lands push the bullet back...it was popular way back in the day when I was benchresting, it was also done in Schuetzen rifle competition and I know some BP shooters that do it with their paper patched loads. This is done in conjunction with carefull load workup and isn't for the uninitiated.

Luck
 
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