Consistent Accurate Bullet Seating Depth

[jcinsa]

Achieving consistent accurate bullet seating depth has been a pet problem of mine for a while.

First observation :

My Stony Point gauge is meant to touch the bullets ogive in the same position that the rifling does.

The seating stem on my Redding Competition Seater definitely does not, instead touching the ogive much closer to the point of the bullet.

This wouldn’t be of any concern if every bullets ogive was precisely the same, but they’re not.

Attempted solution :

I had a new bullet seating stem machined that touches the ogive in the same position as the Stony Point gauge.

This bullet seater stem is very thin, even 'sharp' at the point where it touches the ogive. I don't think this is a problem, as it is a snug fit in the Redding Competition Seater Die, and this supports the thin edge.

Results :

I think they are much better than before, however, I now notice the slop in my 30 year old press, about 2 thou.

I'm in the process of mounting a brand new press that hopefully will improve things.

What do others think ?

Am I barking up the wrong tree?

Have I missed something ?

John

 

[Rtheurer]

Does your rifle know the change in .002 worth of seating depth? Are you trying to find a salution to a problem that has little or no affect on consistant accuracy of your rifle and ammo combination?

I am intrested to hear what our National Champion Bench Rest shooters have to say on this issue. Lots of top shooters post hear that may have set records or won huge matches with there ammo. Do they worry about small amounts of seating depth? When is good enough..... good enough to win?

JC thanks for bringing this up that is a Dern good question.

Russ T

 

[timeout]

I have not shot enough yet to know how much .002" will affect your groups. I do know that for my money, a Wilson seater die and arbor press is better for the bullet seating process than dies used with a conventional reloading press. This is only my opinion. I know others will feel differently. Am only suggesting you try the Wilson/arbor press method. I do admire your quest for perfection.

 

[geordiesniper]

After firing, my cases have less than a quarter of a thou runout and the guage just does not move. Once I resize them with a Nulon die cut with the reamer that produced my chamber, the runout goes to about half a thou. Once I seat the bullet (Berger 180gr VLD) with my Wilson seater (again cut with the same reamer) my runout goes to just less than one thou runout and a few just over.
I do not think my rifle would notice much if the runout went to 2 or 3 thou runout at all as I seat my bullets 10 thou into the rifling. The biggest problem I have at 1000yds f class/benchrest shooting is the wind.
Do not get hung up on such minutae as there are more things to worry about, but it is always nice to get runout under 1 thou but not compulsory!

 

[MVW]

jninca,

Not sure what caliber you are running, but you might find this bullet comparator interesting. Bob pre sorts the bullets to address your initial concern. He seems to think small variations in OAL matter, but for my rifle, probably not so much.

http://greensrifles.com/New_Products.html

Mike

 

[243winxb]

I now notice the slop in my 30 year old press, about 2 thou.

The Redding Competition Seater might not work with this method. Removing slop-This works for an RCBS unit & dies.-Bullet Seating- Sloppy linkage & press spring can cause variation in the COL length. To remove this, a steel washer .061" thick & 1" in diameter is placed over the case onto the shell holder. On seating the bullet, this RCBS press will "cam over" removing any slop or spring coming from the press. No Crimping. Testing 223 & 55gr fmjbt shows a variance of .001" when taking the measurement off the ogive of the bullets.

 

[amlevin]

I now notice the slop in my 30 year old press, about 2 thou.

The Redding Competition Seater might not work with this method. Removing slop-This works for an RCBS unit & dies.-Bullet Seating- Sloppy linkage & press spring can cause variation in the COL length. To remove this, a steel washer .061" thick & 1" in diameter is placed over the case onto the shell holder. On seating the bullet, this RCBS press will "cam over" removing any slop or spring coming from the press. No Crimping. Testing 223 & 55gr fmjbt shows a variance of .001" when taking the measurement off the ogive of the bullets.

I've used something similar. A hardened washer with an OD that just fits through the threaded hole in the press, "glued" to the bottom of the die with some J-B Weld. Kind of a DIY Dead Length Seater.

 

[BoydAllen]

Although Redding tells you not to have the die body touch the shell holder, If you are careful, you can. Just remember that the body is not hardened, and can be distorted with too much pressure. Also, a friend, who has both the Redding and less expensive Forster seaters, thinks that the Forster gives less of the type of variance that you have described. Personally, I would side step the entire issue and use an arbor press type seater.

 

[bozo699]

Although Redding tells you not to have the die body touch the shell holder, If you are careful, you can. Just remember that the body is not hardened, and can be distorted with too much pressure. Also, a friend, who has both the Redding and less expensive Forster seaters, thinks that the Forster gives less of the type of variance that you have described. Personally, I would side step the entire issue and use an arbor press type seater.

Boyd,
I am surprised you didn't finish your post! Gentlemen you cannot nor never will have consistent bullet seating depth unless you have consistent neck tension, you won't have consistent neck tension unless you anneal, sort brass, brush necks, properly fitted to your chamber f/l sizing die, etc,etc,etc. There is much more to consistent bullet seating then just your seating die, of course a quality inline die can't hurt
Wayne.

 

[ThunderDownUnder]

I'm pretty sure JCinSA is bullet seating onto a compressed load of Varget. This means that the Wilson inline dies and arbour press could not be used as not enough leverage and mechanical grunt is available. It also makes bozo699's comment an accurate observation on neck tension being critical for accurate bullet seating, especially on a compressed load that provides a little "springback" on the bullet.

The lapua 308W brass (LRP) is excellent brass and I know John neck turns his cases but cleaning the inside of the necks (brushing) and neck tension may need increasing to better enable consistant bullet seating and OAL for his load. We are talking about ony a couple of thou and it may prove difficult to achieve.

Ian

 

[BoydAllen]

Wayne,
We, in short range benchrest, generally do not anneal, and somehow manage to survive.

As to the speculation about heavily compressed loads, I went back and did not see it in the post that started this thread and did not read anything about that .

Seaters that have a built in crimp may indeed be converted into dead length seaters with addition of some sort of spacer, either fixed to the die or placed around the case, on the shell holder, loose. I like the ingenuity, but it seems to me that having the die be that far off of the shell holder would cause an issue with fit to the round being assembled, the very reason for sliding sleeves and arbor press dies. On the other hand, if boat tails are being seated, in my experience, this all becomes less critical.

One thing that you can do to check your bullets it to put bullets into a loading block, and make up a chart. First measure each bullet with a comparator with an insert that approximates the contact that a seating stem would have, and enter that measurement for each bullet, then remeasure each with an insert that approximates the contact of the barrel throat. Then subtract the smaller number from the larger for each bullet. The variance of these differences will tell you something about the consistency of the bullets. With careful and consistent technique they will represent the distances between where the stem and rifling make contact. If your differences in loaded round length, (measured from the approximate point on the ogive where the leade angle of the throat will make contact, to the cases' heads) correspond to the variiance of the distances between where the stem and the rifling make contact, then your problem is with the bullets, and no amount of fiddling can do any more than keep it to that minimum.

I think that one thing that may be beneficial to determine is how much neck tension is necessarry to achieve the best accuracy with a given load. If little is required, the sizing process may be altered to reflect this reality, with the probable result that uniformity in bullet seating will improve.

 

[Webster]

I don't understand the problem with determining the COAL to touch the rifling with the Stony Point gauge and the seating die touching the bullet at a different location. The gauge determines the length of a particular bullet to touch the rifling. After using the gauge you measure the cartridge length. Then you adjust the seating die to give you the same length. It doesn't matter where the seating die touches the bullet. You just adjust the seater to give you the COAL you want. It has nothing to do with where the seater touches the bullet. Am I missing something? You can buy a 4" digital micrometer at Harbour Freight for $16. I have a Stoney Point Gauge and gave up on it. Every try gave me a completely different number.

 

[BoydAllen]

The curvatures of ogives within the same box of bullets may not be identical, even if the same pointing die was used for them all. This can result in minor variations is the distance from where the seating stem makes contact to where the rifling will. If we assume that even with with perfect bullets that there would be some difference in seating depth due to neck tension, and we understand that sometimes these differences (from variations of neck friction and ogive shape) can in some cases be significant to tune, knowing what is going on with a particular lot of bullets may be a good thing. Of course for most applications all of this gets lost in the noise, BUT if you happen to have a very good rife, in perfect tune, and shooting conditions are optimal, the variation in relationships of chambered bullets to the rifling might show up on the target.....and yes, that is a lot of ifs. Bottom line, it doesn't hurt a thing to check the ogive lengths (not the lengths of ogives , but the the distance from the approximate point of rifling contact to case head) of ALL of your rounds if you are seriously trying win matches...or you can assume that all of your ammunition is identical. This was all a lot simpler when my reloading equipment consisted of a Lee Loader and a plastic headed mallet, and I had just as much fun.

 

[Rtheurer]

. This was all a lot simpler when my reloading equipment consisted of a Lee Loader and a plastic headed mallet, and I had just as much fun.

Indeed sir!

Mr Allen shoots Point Blank Benchrest and Mr Wayne shoots 600 and 1000 yard Bench rest correct? I get alot of good information from both of your posts on this board. Good solid advice. I want to ask this.... Do either of you seat your bullets into the lands for your matches? If you do, I would think consistant neck tension has more to do with consistant accuracy than a couple Thou seating depth? Understand that every stone does not go unturned in your quest to produce the smallest groups. Which is what its all about.
If your jumping your bullets I could see where a small variation in seating depth may indeed affect accuracy. But again this is where Neck tensioin is still the major factor.

Im going out on a limb here and say that if Mr Jim is not shooting Bench rest or is trying to accomplish what a benchrest gun and shooter does, that .002 variation in seating depth is not even worth messing with. I would like Mr Cortina to chime in to see if he does this with his long range FClass ammo. Or Mr Laurie for that matter.
If all your equipment isnt to exacting standards like benchrest then this issue is just lost in the noise of other major variations in your loading and shooting program.

Not trying to discourage anyone from testing and experimenting by anymeans but I get the feeling that sometimes we get caught up in the fine details when more often than not its the guy who does not know how to properly set up and shoot the rifle or read the wind.
Again when is good enough.... good enough to win?

Thanks in advance for all your time and valued input. I think its great that you come here and help out.
RussT

 

[BoydAllen]

Often when I get involved in one of these discussions, I do so with no real information about the shooter, his equipment, and his current level of average accuracy. In the process of the discussion we get into pickin' the fly specks out of the pepper, when, if we had a more complete understanding of the overall situation, the topic would be waay down on the list. To see the difference that some of these finer points might make, you need a state of the art rifle, rest, and an experienced shooter, with wind flags and good weather. Often, I run into a shooter that chooses to focus in on some particular detail, refusing to deal with things that carry more weight. Take care of the big things first. If you are shooting off of lead sled on a pivoting bench, with no flags on a breezy day, with a load that you took a stab at, worrying about some of the smaller details is a complete waste of time. On the other hand, one of the great thing about hobbies is that you can pretty much do it any way that you want to and can afford.

 

[DennisH]

Gentlemen you cannot nor never will have consistent bullet seating depth unless you have consistent neck tension, you won't have consistent neck tension unless you anneal, sort brass, brush necks, properly fitted to your chamber f/l sizing die, etc,etc,etc.

The above is a fact. I started paying attention to neck tension and brass prep. I am definetly getting consistant Seating Depth measurements now. If I seat one that's a little harded to seat, I check it and its always a few thou longer! I put it to the side and keep going.

 

[ThunderDownUnder]

I don't understand the problem with determining the COAL to touch the rifling with the Stony Point gauge and the seating die touching the bullet at a different location. The gauge determines the length of a particular bullet to touch the rifling. After using the gauge you measure the cartridge length. Then you adjust the seating die to give you the same length. It doesn't matter where the seating die touches the bullet. You just adjust the seater to give you the COAL you want. It has nothing to do with where the seater touches the bullet.

I had this exact discussion with jcinsa and I agree with Webster. After you find the lands with the Hornady OAL gauge and measure using the Hornady comparator, you then adjust the bullet seater to the bullet seating depth you want. It doesn't matter a damn that the comparator and the bullet seating stem in the die touch the ogive in a slightly different place, because when you measure the OAL of the seated bullet you use the same Hornady comparator that you used in the AOL gauge! I know that jcinsa has used my reamer for one of his chamberings and with 46+gr of Varget it is a compressed load.

If jcinsa is seating the bullets (HBC 155gr) with a 20+thou jump I really dont think a variance in OAL of 3 thou will matter much at all especially when you add in the tolerance of the measuring equipment. I think its great looking for the perfect bullet seating tool and technique but I think its jousting at windmills trying for less variance than 3 thou between loaded rounds. If its possible I would love to know how its done without seating and measuring every bullet individually that you seat.

Ian

 

[Rtheurer]

OK some things are starting to come together. More information about the shooting and the intended purpose of the ammo. Like Mr Allen has mentioned alot of the time a vauge question is asked without enough particlulars and detailed information and these threads spin off into a 6 page desertation on the most minute things only to find out he is working on a Mark IV Smelly 303 for vintage rifle match shooting.

So Im guessing ( since we still dont have a direct answer) that the OP is either a F Class shooter or a Prone Sling shooter? Shooting a 308 Winchester cartidge with maybe the HBC bullet?
I was told this last Oct that in Queens that the 155gr Sierra and HBC are the only allowed bullet. I was considering all that after I got my A!@#$% handed to me on the Range in Brisbane at the world Long Range Championship. What I wouldnt have given for my 6.5X284 that 3 weeks I was there!!!!!

So Step one.
Get a load that shoots 1/2MOA elevation at the distance your shooting at.
Step two.
Learn how to shoot and read the wind.
Step three
More shooting less tinkering.

Russ T

 

[Erik Cortina]

Does .002" seating depth variation matters?
Yes.

Do I achieve .000" variation in seating depth?
Yes.

Does it matter where your measuring tools contact the ogive?
Yes.

Does .000" variation help with accuracy?
No, it helps with consistency. If your gun is not properly tuned consistent seating depth will not make gun more accurate, but if your gun is tuned, it will shoot tighter with no flyers.

How can some shooters do so well without obtaining .000" seating depth consistency?
They might have perfect ammo, but their measuring tool is measuring at the wrong place. Also, this is where "good" bullet lots and "bad" bullet lots come into play.

 

[amlevin]

On the other hand, one of the great thing about hobbies is that you can pretty much do it any way that you want to and can afford.

Definitely a great hobby. Some days you just want to go to the range and shoot, relaxing and not worrying about anything. Kind of like a day at the Golf Course playing a round with no scorecard or pencil 8) 8)