Seating of bullet

hrlevi1 · January 5, 2011, 09:32 AM

Being relatively new to the reloading hobby - I have a question or two... the first is how to do i know the proper height to set the bullet with respect to the chamber of my rifle? I am reloading 280 Rem. and seem to remember a fellow reloader telling me that the closer I can get the bullet to the lans of the barrel the more accurate it will be. I don't know how to measure this... any help would be appreciated and please excuse my niavity.

I am using cci primers with h4350 powder and a 140 gr. nosler ballistic tip bullet. I'll only be reloading brass that has been fired through my rifle therefore I had not planned to run them through the full length die rather just use the neck sizer die.

Please advise me as I don't want to make too many mistakes.

FlyFish · January 5, 2011, 10:16 AM

There are basically two relatively simple ways that I'm aware of to determine the cartridge OAL that will be just off the lands.

1. The trial-and-error method involves seating a bullet in a dummy cartridge to a depth you know won't contact the lands, which you should be able to figure out with a little fiddling, and then repeatedly seat it a bit further out and chamber it until it does make contact, then back off a couple thousandths. You chamber the dummy cartridge at each length and look for the marks the lands make on the bullet (some people use a candle to "smoke" the bullet to help see the marks). I usually use a kinetic bullet puller to "unseat" the bullet a bit more than I want each time, then reseat it in my press to the longer length I'm looking for.

What I prefer to do, however is:

2. Take one of the bullets you'll be using (just the bullet), drop it into the breech end of the barrel and give it a light tap with a stick or something to stick it there lightly. Carefully insert a cleaning rod from the muzzle until it just touches the bullet and mark the rod at the muzzle. Then tap the bullet out, close the action, and insert the rod from the muzzle again until it's flat on the bolt face, and mark it again. The distance between the two marks is the OAL at which the bullet is touching the lands. I then make up a dummy round a couple of thousands shorter than that measurement and use procedure (1) to make sure it's not actually in contact with the lands at that OAL.

I would recommend full-length sizing until you have more experience reloading, and maybe after that as well. There are many experienced reloaders/shooters who make a convincing argument that neck sizing doesn't provide any real advantage in a typical hunting rifle.

noylj · January 5, 2011, 10:17 AM

You can use the Hornady Lock-N-Load Overall Length Gage ($30) with a .280 modified case from Hornady ($12), or the Frankford Arsenal Cartridge Overall Length Gage ($17).
What some people do is take a case and saw two slits down the case neck. The case should be able to hold the bullet but the bullet should slide into the case when it hits the lands. This will give you the max COL for that bullet, provided it doesn't stick in the rifling.

dardascastbullets · January 5, 2011, 02:53 PM

The RCBS Case Gauge is an excellent tool for determining the headspace and the seating depth for your 280. It is simple to use. Check it out - I am sure that you will be more than happy with it!

Doodlebugger45 · January 5, 2011, 03:13 PM

I use the #2 method described by FlyFish. It's simple and cheap if you have lots of different calibers. I use a wooden dowell rod. I use a sharp knife blad to make the marks because you want something pretty thin and definite to measure. It works pretty good. In most cases you'll find you can seat bullets out quite a bit farther out than what the manuals suggest. In some cases, they will stick out so far that they won't even fit into the magazine.

4runnerman · January 5, 2011, 03:42 PM

Being relatively new to the reloading hobby - I have a question or two... the first is how to do i know the proper height to set the bullet with respect to the chamber of my rifle? I am reloading 280 Rem. and seem to remember a fellow reloader telling me that the closer I can get the bullet to the lans of the barrel the more accurate it will be

That is not always the case. Some guns like it right on lands other off lans.
You do need to determine your max length and work from there. Always reduce loads while testing and watch for pressure signs. Many studies have been done on this touching the lans and has always been proven to be a gun by gun basis. I know this don't help you to much,but it is trial and error for everyone. I would suggest the step ladder method for load work ups. It works wonders

PA-Joe · January 5, 2011, 03:49 PM

For new reloaders it is best to stick with the bullet manufacturer's COL. After you get good at reloading then you can start making changes.

For the beginner you really have to learn the right way to make consistent powder drops, crimps and priming. Then you can start playing with other factors.

wncchester · January 5, 2011, 04:07 PM

PA Joe is correct for noobs; Either follow the book suggestions, compare length with a factory round or seat and crimp to the canalure.

maillemaker · January 5, 2011, 04:53 PM

I tried seating by OAL and found with some Oregon Trail 230 grain LRN bullets that they were not seated sufficiently deep. See the left-most cartridge in this picture:

http://www.forth-armoury.com/temp/bullets/P1010197.JPG

So I seated the bullets until the shoulder of the bullet was flush with the case mouth.

Steve

700cdl · January 6, 2011, 01:47 AM

Hey there Flyfish, I use the number 2 method you described and have had really good results. It is still an iffy process because a lot of bullets have some pretty inconsistent olgive location, so what I do is when I've found the depth I back off by about .005" or so, to prevent some from touching the bore. I have found Speer to have a pretty reliable olgive compared to a lot of the other common brands of simular cost.

700cdl · January 6, 2011, 01:56 AM

Thanks PA-Joe for reminding me about new comers. I totally agree with you to focus on the basic process and seat according to listed COL unitl one has gained more experience and knowledge. And yes, keep the loads nice and average while learning, working things up as experience permits. Just savor the excitement of loading your own stuff for now, customizing and tweaking loads will come in do time.

wncchester · January 6, 2011, 12:19 PM

"..remember a fellow reloader telling me that the closer I can get the bullet to the lans of the barrel the more accurate it will be."

As an absolute, he was wrong; it CAN be true but it's rare in factory sporters. Most shoot best with a jump from 20 thou to as much as five times that much. Thus, finding the exact point of rifling contact is a general thing, little or nothing is gained by finding it to an accuracy of better than maybe 10 thou.

FlyFish · January 6, 2011, 12:35 PM

Quote:

Hey there Flyfish, I use the number 2 method you described and have had really good results. It is still an iffy process because a lot of bullets have some pretty inconsistent olgive location, so what I do is when I've found the depth I back off by about .005" or so, to prevent some from touching the bore. I have found Speer to have a pretty reliable olgive compared to a lot of the other common brands of simular cost.

That's a really good point about inconsistencies in the ogive. I was loading up a batch of several thousand .223s recently, and was getting really odd variability in OAL - enough so you could easily see it without measuring. I thought it was something I was doing but eventually figured out it was variability in the ogive in the Winchester bulk bullets I was using - along with some inconsistencies in the placement of the cannelure that made things look worse than they actually were. For AR plinking ammo I don't really care, but for more precise work the safety procedure you describe makes a lot of sense.

**Unclenick** · January 6, 2011, 12:36 PM

Yep, exactly. Seating depth has to be tuned to the gun. Walt Berger say's they've found the long ogive VLD's want to be as much as 0.165" off the lands for best accuracy. Stubbier nose forms usually wind up closer, but YMMV.

Note the Dan Newberry's method is usually able to get 1/2 moa loads without any special tools or seating depth. That's already pretty good tuning. That's the place to start, IMHO.

Once you have the most accurate load established at a standard COL, you can play with tuning seating depth to try get the groups still smaller. Back the established load down 10% and try to find a seating depth sweet spot by varying depth instead of powder charge in one of those same Newberry round robins. When you find that, then adjust the powder charge again.

January 5, 2011, 09:32 AM	#1
hrlevi1 Junior Member Join Date: January 5, 2011 Posts: 1	Seating of bullet Being relatively new to the reloading hobby - I have a question or two... the first is how to do i know the proper height to set the bullet with respect to the chamber of my rifle? I am reloading 280 Rem. and seem to remember a fellow reloader telling me that the closer I can get the bullet to the lans of the barrel the more accurate it will be. I don't know how to measure this... any help would be appreciated and please excuse my niavity. I am using cci primers with h4350 powder and a 140 gr. nosler ballistic tip bullet. I'll only be reloading brass that has been fired through my rifle therefore I had not planned to run them through the full length die rather just use the neck sizer die. Please advise me as I don't want to make too many mistakes.

January 5, 2011, 02:53 PM	#4
dardascastbullets Senior Member Join Date: July 20, 2008 Location: Essexville, MI Posts: 164	The RCBS Case Gauge is an excellent tool for determining the headspace and the seating depth for your 280. It is simple to use. Check it out - I am sure that you will be more than happy with it! __________________ Matt Dardas

January 6, 2011, 12:36 PM	#14
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,743	Yep, exactly. Seating depth has to be tuned to the gun. Walt Berger say's they've found the long ogive VLD's want to be as much as 0.165" off the lands for best accuracy. Stubbier nose forms usually wind up closer, but YMMV. Note the Dan Newberry's method is usually able to get 1/2 moa loads without any special tools or seating depth. That's already pretty good tuning. That's the place to start, IMHO. Once you have the most accurate load established at a standard COL, you can play with tuning seating depth to try get the groups still smaller. Back the established load down 10% and try to find a seating depth sweet spot by varying depth instead of powder charge in one of those same Newberry round robins. When you find that, then adjust the powder charge again. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

January 5, 2011, 10:16 AM	#2
FlyFish Senior Member Join Date: January 20, 2009 Location: Overlooking the Baker River Valley Posts: 1,731	There are basically two relatively simple ways that I'm aware of to determine the cartridge OAL that will be just off the lands. 1. The trial-and-error method involves seating a bullet in a dummy cartridge to a depth you know won't contact the lands, which you should be able to figure out with a little fiddling, and then repeatedly seat it a bit further out and chamber it until it does make contact, then back off a couple thousandths. You chamber the dummy cartridge at each length and look for the marks the lands make on the bullet (some people use a candle to "smoke" the bullet to help see the marks). I usually use a kinetic bullet puller to "unseat" the bullet a bit more than I want each time, then reseat it in my press to the longer length I'm looking for. What I prefer to do, however is: 2. Take one of the bullets you'll be using (just the bullet), drop it into the breech end of the barrel and give it a light tap with a stick or something to stick it there lightly. Carefully insert a cleaning rod from the muzzle until it just touches the bullet and mark the rod at the muzzle. Then tap the bullet out, close the action, and insert the rod from the muzzle again until it's flat on the bolt face, and mark it again. The distance between the two marks is the OAL at which the bullet is touching the lands. I then make up a dummy round a couple of thousands shorter than that measurement and use procedure (1) to make sure it's not actually in contact with the lands at that OAL. I would recommend full-length sizing until you have more experience reloading, and maybe after that as well. There are many experienced reloaders/shooters who make a convincing argument that neck sizing doesn't provide any real advantage in a typical hunting rifle.

January 5, 2011, 10:17 AM	#3
noylj Senior Member Join Date: October 22, 2007 Location: Between CA and NM Posts: 860	You can use the Hornady Lock-N-Load Overall Length Gage ($30) with a .280 modified case from Hornady ($12), or the Frankford Arsenal Cartridge Overall Length Gage ($17). What some people do is take a case and saw two slits down the case neck. The case should be able to hold the bullet but the bullet should slide into the case when it hits the lands. This will give you the max COL for that bullet, provided it doesn't stick in the rifling.

January 5, 2011, 03:13 PM	#5
Doodlebugger45 Senior Member Join Date: April 15, 2009 Location: Wyoming Posts: 1,717	I use the #2 method described by FlyFish. It's simple and cheap if you have lots of different calibers. I use a wooden dowell rod. I use a sharp knife blad to make the marks because you want something pretty thin and definite to measure. It works pretty good. In most cases you'll find you can seat bullets out quite a bit farther out than what the manuals suggest. In some cases, they will stick out so far that they won't even fit into the magazine.

January 5, 2011, 03:42 PM	#6
4runnerman Senior Member Join Date: January 16, 2010 Location: Minnesota Posts: 3,577	Being relatively new to the reloading hobby - I have a question or two... the first is how to do i know the proper height to set the bullet with respect to the chamber of my rifle? I am reloading 280 Rem. and seem to remember a fellow reloader telling me that the closer I can get the bullet to the lans of the barrel the more accurate it will be That is not always the case. Some guns like it right on lands other off lans. You do need to determine your max length and work from there. Always reduce loads while testing and watch for pressure signs. Many studies have been done on this touching the lans and has always been proven to be a gun by gun basis. I know this don't help you to much,but it is trial and error for everyone. I would suggest the step ladder method for load work ups. It works wonders

January 5, 2011, 03:49 PM	#7
PA-Joe Senior Member Join Date: June 9, 2010 Location: NEPA Posts: 909	For new reloaders it is best to stick with the bullet manufacturer's COL. After you get good at reloading then you can start making changes. For the beginner you really have to learn the right way to make consistent powder drops, crimps and priming. Then you can start playing with other factors.

January 5, 2011, 04:07 PM	#8
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	PA Joe is correct for noobs; Either follow the book suggestions, compare length with a factory round or seat and crimp to the canalure.

January 5, 2011, 04:53 PM	#9
maillemaker Senior Member Join Date: August 30, 2010 Posts: 1,635	I tried seating by OAL and found with some Oregon Trail 230 grain LRN bullets that they were not seated sufficiently deep. See the left-most cartridge in this picture: http://www.forth-armoury.com/temp/bullets/P1010197.JPG So I seated the bullets until the shoulder of the bullet was flush with the case mouth. Steve

January 6, 2011, 01:47 AM	#10
700cdl Senior Member Join Date: December 6, 2010 Posts: 216	Hey there Flyfish, I use the number 2 method you described and have had really good results. It is still an iffy process because a lot of bullets have some pretty inconsistent olgive location, so what I do is when I've found the depth I back off by about .005" or so, to prevent some from touching the bore. I have found Speer to have a pretty reliable olgive compared to a lot of the other common brands of simular cost.

January 6, 2011, 01:56 AM	#11
700cdl Senior Member Join Date: December 6, 2010 Posts: 216	Thanks PA-Joe for reminding me about new comers. I totally agree with you to focus on the basic process and seat according to listed COL unitl one has gained more experience and knowledge. And yes, keep the loads nice and average while learning, working things up as experience permits. Just savor the excitement of loading your own stuff for now, customizing and tweaking loads will come in do time.

January 6, 2011, 12:19 PM	#12
wncchester Senior Member Join Date: December 1, 2002 Posts: 2,832	"..remember a fellow reloader telling me that the closer I can get the bullet to the lans of the barrel the more accurate it will be." As an absolute, he was wrong; it CAN be true but it's rare in factory sporters. Most shoot best with a jump from 20 thou to as much as five times that much. Thus, finding the exact point of rifling contact is a general thing, little or nothing is gained by finding it to an accuracy of better than maybe 10 thou.