boolit depth with gas check

[leowa]

I just started reloading 8MM rounds. I have 165 gr boolits with gc. As far as I have read you should not seat the gc below the neck of the shell. If I load the shell that way the round will not chamber correctly. Using the Lyman reloading guide oal to 2.730 the round seams to work fine, But the gc is below the neck. which is correct.


Thanks

[Ben]

Some of my most accurate loads have the g/c below the case neck.

There are an awful lot of " old wives tales " spread around.

As you load and learn more, you'll be able soon to sort out the fact from the fiction.

[rays308]

1+ what Ben said

Its said that boolits are more accurate with the gas check located in the neck. I haven't seen an issue.

Boolit fit is MUCH more important.

Some folks use a dacron filler when gas checks are below the neck. Fillers only get me a little less smoke from the lube on GC loads.
My rule of thumb on fillers is to use 2 grains less of powder with a dacron filler. Brings the pressure back to where I wanted it.

Larry Gibson gave a very good explination of fillers in a couple of posts. Below is a quote from one of his posts.



I have for many, many years found dacron (polyester fill) to be the best "filler".

I don't use the dacron filler or a wad with the fast to medium burning "fast" pistol /shotgun type powders. I find one of these fast burning powders that is fast enough to ignite and burn efficiently at the velocity I want and avoid using a filler with them.

I almost always use the dacron filler in rifle cases with the slower “fast” burning powders (4227, 4759, 5744, 4198, etc.), the medium burning powders (RL7, 3031, 4895, etc.) up through the slow burning powders (RL19, AA4350, H4831SC, RL22, 3100, etc.) that give around 80% or less loading density. The dacron filler is used only between the powder and base of the bullet.

The “dacron” is polyester fill as commonly found in pillows and toys. It also comes in sheets called “batting”. It can be obtained very reasonably at most any fabric store.

The dacron batting comes in various thicknesses. I prefer that which is about 5/8" thick. My wife recently bought me 10 yards which will give many, many thousands of cast bullet loads. With this current batch of batting I cut it initially across the width into strips about 3/4" wide. I then "eyeball" cut 1/2" wide chunks which is close to 3/4 gr.

A smaller chunk is cut for 1/2 gr and larger for a larger amount. I've cut some chunks that weight 1/2, 3/4, 1, 1 1/4 and 1 1/2 grs and have them in a "snack" baggie stuck on a poster board above my loading bench for quick reference when I need to cut new chunks. The batting will run thin and thick throughout the sheet so I again just "eyeball it" based on the thickness of the batting when cutting the chunks.

Pretty extensive tests have demonstrated that the weight of the filler does not have to be exact, only close. What is important is that there is enough so that it “fills" the space between powder and bullet. A little too much hurts nothing but too little poses problems. That's why I have the different size "chunks" so I can use the right size for the case capacity I am filling. For example; with most medium burning powders (3031, 4895, 4064) in and '06 to function an M1 a 3/4 gr dacron filler is about right. With slower powders that give a higher loading density like 4831 a 1/2 gr filler is about right.

I use a section of .22 cal cleaning rod in cartridges of .30 - .375 cal to push the Dacron chunk inside the case just so it is all in. The 6 to 10" section gives plenty to hold onto and sufficient "feel". Merely hold the chunk of dacron over the case mouth and shove it in with the rod. Sometimes it takes a couple three pokes to ensure all is inside the case mouth. I poke the chunks in until the are at the bottom of the neck or at least all in the case. It doesn’t matter. What you want is to let the base of the bullet finish pushing it down and adding any compression. Thus I do not push it down on the powder but let the bullet do that when the bullet is seated. Using the right size chunk of dacron this method then provides a "filler" in the air space between the powder and base of the bullet.

A small length of coat hanger works for the .22-7mm cartridges and an unsharpened pencil works well for .45 cals.

Larry Gibson

Shoot'em, If they're accurate, shoot some more.

[Von Gruff]

A couple of points to think about is that if the GC is firmly attached then this negates most of the concerns which mostly stem from a tighly sized neck and a less than firm GC. When trying to de-boolit with the likes of an inertia hammer it is likely to leave the GC in the neck and leads to the assumption that this will happen in the rifle, effection accuracy, and not taking into account that there is pressure behind the GC to keep it on the boolit.
I use Wilson dies and this only partialy neck sizes my 7x57 brass, (like the 8x57) which leaves the 2 thou larger neck- shoulder dia in place and this eases the entry into the neck for the GC boolit and the mouth dia is sized to 2 thou and with springback is only holding the boolit with 1 - 1 1/2 thou grip so is also less likey to pull the GC off.

Von Gruff.

[1Shirt]

As usual, I agree with Ben. I use dac filler with most all rifle loads except for the fast burning shotgun powders which do not need fillers. Like some of the others, have never seen a difference in accuracy below the neck or in the neck. One factor using fillers and below the neck blts is that the filler prevents (I think) possible contamination of the powder by lube below the neck.
1Shirt!:coffeecom

[PatMarlin]

So many variables, so little time.

That's what I love about cast boolits. If the hard and fast rules where set in stone, it would become boring at some point. HOW many years have folks been shooting cast, and still today, old rules are broken, new innovations still keep coming? Truly remarkable really.

[Larry Gibson]

Not sure I would confuse "variables" with "rules". Seating GCs below the case neck is frought with variables. You can get away with it at times and other times not. It depends on many variables like alloy hardness, depth of seating into case, powder used, psi obtained, fit of bullet to throat, etc. ad nauseum......I could go on and on but the point is if you are getting acceptable accuracy with GCs seated below continue but please don't make it a "rule" that you can because somewhere down the road you will get bit. It has been "proven" both ways. I make it a general practice not to seat the GC (the top edge anyway) below the case neck unless a particular bullet design requires it. I do so because I have been "bitten" enough times in the past and simply chose to remove that "variable" from the get go. Best to use a bullet design where you don't have to seat the GC into the case that far.

What is "acceptable" is also another very broad variable. Some find 4-6" groups at 50 yards "acceptable". Others won't accept that at 300 yards. Depends on the accuracy capability of the rifle, the casting and loading ability of the loader and the marksmanship abilities of the shooter. Marksmanship, even when shooting from a bench, is an aquired skill that must be learned and maintained. Many do not obtain a sufficient level of marksmanship skill and blame the lack of accuracy on the load or the rifle instead of where it really belongs.

Larry Gibson

[leowa]

Do I need to use fillers with powders like 2400.

[Ben]

leowa :

In my opinion, NO !

[Ben]

So many variables, so little time.

That's what I love about cast boolits. If the hard and fast rules where set in stone, it would become boring at some point. HOW many years have folks been shooting cast, and still today, old rules are broken, new innovations still keep coming? Truly remarkable really.
__________________________________

Pat :

Last week, I shot a group at 200 yds. with one of my rifles, .....a .308 Win. with an Adams and Bennet F-54, Hvy. stainless flutted barrel. 5 rounds at 200 yds. The group was 5/8 " wide and 1.25 " high.

Guess what, it was shot with the Lee 155 grs. SKS spire pt. g/c bullet sized to .310 with 17.5 grs. of 2400 and a Wolf LR primer.

For years, old time casters have been saying that you're wasting your time trying to get accuracy out of a cast spire pt. bullet in a rifle. So much for that old saying.....................

[PatMarlin]

THAT is great news at the moment especially since I'm dusting off my RCBS 270 spire point mold purchased 10 years ago, never used and was going to cast up some loads for my Browning.

I've never tried a spire point mold, but the old argument never made sense to me. I figured well, if the bullet was out of balance or not concentric for some reason, then well OK. But with copper shooting fine in spire points, why not?

What alloy did you use Ben?

[Ben]

What alloy did you use Ben?
____________________________

ACWWs with about 2% tin added.

[405]

I agree with what Larry said. The least of "getting bit" is poor accuracy. I make every effort to avoid seating bullet bases below the neck... gas checked or not. In any case (no pun), no matter where the bullet base is seated, my first rule of gas check use is to make sure the check is fully, firmly and squarely crimped onto the shank.... learned the only way some learn.... experience and the hard way.