Adjusting bullet seating using barrel lands

beenjammin

beenjammin

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Aug 17, 2006
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#1
A buddy told me yesterday about an article he read where someone was barely seating a bullet in prepped brass (not primer or powder) coloring the bullet and chambering the shell allowing the lands to seat the bullet rubbing the bullet where they touched. Then he adjusted the seating die a few thousandths from the mark where the bullet just barely clears the lands. Reported 3/4 inch groups came down to 1/4 using the same ammo, charge, everything.

Is this common practice? It seems like a pretty good idea for the ammo for a designated rifle.

Being new to the reloading game, I wanted to ask you veterans about this. Forgive me for not using correct terminology.
 
#2
Re: Adjusting bullet seating using barrel lands

That is a fairly common way to find the lands. Once found, you can can accomplish a lot with that information. You can then know how much you are jamming or jumping the bullet and find out what your rifle likes. It also allows you to "shortcut" some things like just starting a vld bullet with a ten thou jam and knowing its going to shoot great and not wasting lots of loading and testing time.

Another way of finding your lands is to take a prepped case (no bullet powder or primer) and making cuts into it, 3 works good, in the neck to put a bullet in with less tension and simply cambering the round. The lands will push the bullet into the case until its chambered and then take it out. You can extract measurements from that dummy round and the then keep it for future use.
 
#3
Re: Adjusting bullet seating using barrel lands

Austin, I do the same but with a case with not enough neck tension. After resizing a case with a bushing not small enough, you can put a bullet into the case, chamber it and measure it after extracting to get the precise distance to the lands. Helps you know where you are in relation to the lands for better reloading.
 
#4
Re: Adjusting bullet seating using barrel lands

Be aware that MOST factory chambers are too long to properly do this. Yes some will work doing this. Read the many threads about "touching the lands". But to do it properly you need a custom chamber, usually.

Read a lot more before you try this. This method can cause tremendous pressure spikes with a hot load. That can lead to getting a face full of bolt.

Use extreme caution.
 
#5
Re: Adjusting bullet seating using barrel lands

heed victors warning. I usually have to back my hotter loads off about 2-3% when jamming into the lands from a load that i was jumping.

On another note just pushing a extra long round into the chamber does not find you lands but it gets you close enough to seat a little deeper until the marks start to dissapear. I use 000 steel wool to scuff up the bullet and it makes it easier to see the marks. I have ran comps where my gun like to shoot when i was seating 30-40 thou deep into the lands and the bullets self seat but it was not the best method of finding out where the gun shoots its best at. When i do this its usually jammed about .03" after it has seated itself. Now the ammount of neck tension you are using can cause you problems. If you have more then .002" a side of tension then its not gonna be easy to get this done.
 
#7
Re: Adjusting bullet seating using barrel lands

Good points about not jamming a stiff load. Always start with a reduced load and work up when changing anything. I only find the lands in the initial load development. When I get a load that performs I only recheck every 500 rounds or so and even then maybe bump the load a tenth of a grain or two to maintain original velocity while chasing the lands.

I also very rarley run loads on the high end of the pressure/speed curve, they seem not to group as well.
 
#8
Re: Adjusting bullet seating using barrel lands

thanks for the warnings. I was afraid of the pressure as well. Bolt face is not something I want to happen.

I was using the maker tecnique as well. The acutually backing off the mark some to set the die. I dont want it touching the lands, but close to them.

Id be shooting on my AW. So not a match chamber. It was long. This is why i got concerned.
 
#11
Re: Adjusting bullet seating using barrel lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">I use a "Sharpie" marker to color the bullet. That gives a better contrast against the scrape of the barrel lands. </div></div>

I was warned by a very well known gun smith to never use marker in my chamber or dies. I will tip a bullet with marker once in a while just so i know what they are. He told me it can cause pitting or eroding in dies or your chamber. Something to do with the chemicals in the marker building up and just sitting there or burning. I cant remember exactly but he told me that it ruined a few of his dies so he stop using it real quick.
 
#12
Re: Adjusting bullet seating using barrel lands

I designed the <span style="font-weight: bold">Digital Headspace Gauge </span>for measuring chamber clearance (at the shoulder) that YOUR handloads have in YOUR particular chamber. It <span style="font-weight: bold">ALSO</span> helps you measure your bullet seating (back from the rifling). There's no need to balance your case on the blade of calipers, and you don't need a collection of different size bushings either. very easy to use. Check it out at www.LARRYWILLIS.COM

- Innovative
 
#13
Re: Adjusting bullet seating using barrel lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NotAGuru</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">I use a "Sharpie" marker to color the bullet. That gives a better contrast against the scrape of the barrel lands. </div></div>

I was warned by a very well known gun smith to never use marker in my chamber or dies. I will tip a bullet with marker once in a while just so i know what they are. He told me it can cause pitting or eroding in dies or your chamber. Something to do with the chemicals in the marker building up and just sitting there or burning. I cant remember exactly but he told me that it ruined a few of his dies so he stop using it real quick. </div></div>

Personally I also clean the barrel and my dies every so often. White board markers use alcohol and permanent markers usually use toluene. In 35 + years I can't say I have seen this happen. I'll have to see it under labratory conditions to believe it.
 
#14
Re: Adjusting bullet seating using barrel lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NotAGuru</div><div class="ubbcode-body">heed victors warning. I usually have to back my hotter loads off about 2-3% when jamming into the lands from a load that i was jumping.

On another note just pushing a extra long round into the chamber does not find you lands but it gets you close enough to seat a little deeper until the marks start to dissapear. I use 000 steel wool to scuff up the bullet and it makes it easier to see the marks. I have ran comps where my gun like to shoot when i was seating 30-40 thou deep into the lands and the bullets self seat but it was not the best method of finding out where the gun shoots its best at. When i do this its usually jammed about .03" after it has seated itself. Now the ammount of neck tension you are using can cause you problems. If you have more
then .002" a side of tension then its not gonna be easy to get this done. </div></div>

ditto. This is the way I go on seating depth.



ditto for me
 
#15
Re: Adjusting bullet seating using barrel lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NotAGuru</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Victor N TN</div><div class="ubbcode-body">I use a "Sharpie" marker to color the bullet. That gives a better contrast against the scrape of the barrel lands. </div></div>

I was warned by a very well known gun smith to never use marker in my chamber or dies. I will tip a bullet with marker once in a while just so i know what they are. He told me it can cause pitting or eroding in dies or your chamber. Something to do with the chemicals in the marker building up and just sitting there or burning. I cant remember exactly but he told me that it ruined a few of his dies so he stop using it real quick. </div></div>

Personally I also clean the barrel and my dies every so often. White board markers use alcohol and permanent markers usually use toluene. In 35 + years I can't say I have seen this happen. I'll have to see it under labratory conditions to believe it. </div></div>

Understandalbe Victor. Was just something i was told by someone who i really trust. Maybe it was another problem that caused it by I figure it was best not to take the chance. You can ask Bruce Baer about it if you really want.
 
#16
Re: Adjusting bullet seating using barrel lands

Well guys i just got back from the range. And this has made a dramatic impact on my AIAWs accuracy. Today. 1 hole shot groups. I seated until i saw nomarks from the lands, i did use a sharpie. It like night and day. Ill post some results of two groups with the same lot powder,same lot bullets, same charge. The only difference being seating depth. I am amazed.
 
#17
Re: Adjusting bullet seating using barrel lands

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: cinosbus</div><div class="ubbcode-body">The Hornady L-N-L (Stoney Point) COAL tool and modified cases make this job a lot easier. I'd say mine was definitely worth the money. </div></div>
+1. Used with a wood dowel from the muzzle end, you can really feel the lands stick and get really precise.
 
#18
Re: Adjusting bullet seating using barrel lands

Seating into or really near the lands is fairly new for me, although I've been reloading for many years. I had limited myself to mag. length (3.340" 300 Win. Mag). I have 200g SMK shooting very close to 1/2 moa at this OAL, but am being seduced by the superior BC's of the heavier bullets. Thus the new territory as I've heard (and found) they aren't as jump tolerant.

I loaded some 208 Amax's to .050" off the lands (totally random number) and they shot OK (around 1 moa) but not good enough to continue.

Can I expect a dramatic improvement if I load them into or just at the lands? Thoughts on how to narrow this down without sending lots of bullets downrange?

Thanks

John
 
#19
Re: Adjusting bullet seating using barrel lands

jrob300, someone with more 30 cal. bullet experience than me will chime in, but it made a huge improvement with my 7wsm and 180 berger vld's. I started out shooting the 175 matchkings mag length (jumping them around .07-.08)and they shot good around 1/2+ moa, but I wanted to shoot the 180 berger. I tried jumping it from mag length with not much success, but when I loaded the bergers .010 into the lands it started shooting less than 1/2 moa consistently. Try shooting them in the lands and see what happens. That is the fun (sometimes not so fun) thing about this hobby--we have so many variables and choices. Just remember, you will increase pressure when you load @ or in the lands--start low. Good luck
 
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