Improving accuracy

[sloughfoot]

In 2 1/2 years of shooting cast bullets from my 308 I have learned a lot. Ilearn what not to do more than what to do and that has greatly improved my accuracy. But for whatever reason from time to time there will be that one bullet in a group that just doesn’t want to hang out with the rest. I can only surmise that this has to do with something during the loading process. I have noticed every once in a while I’ll have a bullet that doesn’t seem to sit square in a case but will load in chamber fine. I usually pull those and redo them. What do you suggest to improve bullet seating squareness? 307965

[Bigslug]

Possibly a little more case mouth bell. Start as close to straight as you can.

Check the die periodically for lube goobers. . . or for lube goobers coming loose from inside the die and coming out on the nose of the bullet.

Seat the bullet about halfway, back the ram, rotate cartridge half a turn, finish seat.

Also check your bullet bases for clean sprue cuts. If you have protrusions, that can cause the sort of dispersion you're seeing. Check the sprue plate flatness, tightness, and overall function.

[FredBuddy]

In my 30-30's, I found that using the NOE expander
which is just .001-.002 smaller than the diameter of
the boolit contributes to straighter seating. It has other
benefits also. Then I finish with a Redding taper
crimp die.

[MUSTANG]

I will go further back in the rabbit hole:

(1) Are you doing a good flux of the Alloy?
(2) Are your labels/or bottom pour spout nice and clean also? No rough alloy in the spout or labels (similar to the dross you skim from top).
(3) is your alloy at correct temperature and is your mold nice and warm (cast and dispose of first 5 or 6; or preheat mold on electric single burner heater)
(4) ensure your mold closes exactly the same each time (Trying to avoid an out of round boolit cast; sizing may not fully restore a boolit to roundness, with one side heavier causing less stability in flight). I used to find this an issue with some of the Lee Molds/Handles as they became worn.

The areas of concern I mention above can lead to either an entrained piece of dross inside the boolit or a void. Resulting in that "Flyer" from the group in a boolit so affected.

For accuracy - perfection in each cast boolit is goal. One can also weigh each boolit and reject those outside of your self imposed weight variation range.

[charlie b]

Hopefully someone like Larry Gibson will weigh in here. If not go look up his posts on how he prepares bullets andd cartridges.

Fliers. Yep, the bane of my existence, even after doing everything I can to avoid them. The reasons can be many, but, you have found one of them, cartridge runout.

I minimized it by fixing my seating die. I also load jacketed stuff and use the Redding competition dies for those, but, my cast bullets won't fit in that die. So, I looked at my Lee seating die. Turns out the 'sliding' portion of the die was a bit 'sloppy' in fit. I added a shim in the die body to reduce that to a minimum. I also modified the seating stem to better fit the nose of the bullet (Dremel grinding bit with the stem spun in a drill). This seemed to make most of the runout get a lot smaller.

The other thing that helps me is the Lee collet neck sizing die. Makes the necks concentric to the rest of the case. I use a minimal flare, just enough so the gas checked base fits.

I shoot bore riders. So, I make sure the nose section is a precise fit to the bore, tight enough it takes a bit of a rap on the bolt handle to remove one from the barrel. I seat the bullets so the first drive bands engage the rifling. My reasoning is the '2 point' fit makes sure the bullet is started straight in the bore.

Besides trying to be very consistent in casting I also weight sort in 0.1gn batches. The heaviest ones are reserved for when I want 'extra' accuracy as then tend to group better, probably due to fewer or smaller voids in the bullet.

charlie

[waco]

A good inline benchrest seating die.

[405grain]

The other guys have made some very good points. Clean alloy, proper casting technique, visually inspecting each bullet for defects after casting, weight sorting the bullets, and only then do we get to the actual reloading. You're shooting 308 Winchester. In order for others to be more helpful please tell us more about your load. That way we can see if your problems might be associated with powder choice, velocity, choice and style of bullet, etc. Here's one thing that I do with all my cast bullet loads: I do the bullet seating and case crimping as two completely separate operations. When I remove the case mouth bell, or crimp the case on a revolver round, I always seat the bullet first with the die body slightly backed out. Then, after the bullets are seated to depth, I back the seating stem out and set the die body for the amount of crimp I want. Then I run all of the cartridges back through the die. The reason that I do this is because if I were to seat & crimp in one operation (like with jacketed bullets), the crimping operation will happen while the bullet is still slightly moving past the case mouth. This can cause surface damage to the cast bullet that isn't necessarily visible on the cartridge, but might show up later on the target.

Another factor that you might mention is the brand of your reloading dies. I've had terrible luck with Hornady dies while doing cast loads. I believe that these dies were designed to work with jacketed bullets, and their features are not a good match for cast loads. The Hornady seating die has a sliding tube inside the die body that's supposed to center and guide the bullet as it's seating. It seems that the crimping shoulder is inside this sliding sleeve. With cast loads that sleeve gets stuck sometimes while the reloading press is still on the up stroke. This crushes the mouth of the case into the sides of the bullet, ruining that cartridge. Generally I was loosing between 6 and 10 cartridges this way out of every 100. I have switched over to all RCBS and Redding dies and no longer have any problems. Are you using a brand of dies that has a sliding internal tube in the seating die?

[725]

Much like BigSlug, I "spin" the case when the bullet is atop and being entered into the seating die. I don't just give it a half turn, but rather keep turning it as it enters the seating plug. Takes the wiggle out and lends itself to having the bullet go in square & plumb.

[243winxb]

Sort cast bullets by weight, before size, lube & GC. Cast has air bubbles.

Use a bushing fl die to not over work the necks. Expand with M die.

Benchrest prep brass, sort by weight.

Add linotype to get BHN 15 or harder. Avoid slump & skid.

[charlie b]

A good inline benchrest seating die.

I have one (Redding Competition). My .310 size bullets don't fit. I had some less expensive jacketed bullets that would not fit it either, they were just under .309. That's why I 'fixed' the Lee seating die.

[megasupermagnum]

Unfortunately problems like this can have multiple causes with no real way to know for sure what the problem is. I do know what you mean by some appearing to have seated uneven in a case. You will get suggestions for the NOE plugs, but they wont help you with this. I've tried them. I've tried Lee plugs. I've tried only flaring plugs. The only surefire way I've found to fix this is to use less neck tension to begin with. There isn't much you can do with a standard expander ball sizing die. My preferred method for sizing bottleneck rifle brass is in a 2 step process. The first is a body only sizing die. The second is in a Lee necksizing die. The type of body only die you use does not matter. In my case I modified my standard Lee sizing dies by drilling out the neck portion with a drill bit. Reloading dies are very hard steel and you will probably want carbide tip drill bits. I used normal HSS, but had to sharpen them. Go slow, and use lots of lube in a drill press. Hold the die with a 7/8" nut in the vice. In 308 Win I used an 11/32" drill bit. There are two main reason why I have gravitated to this setup. The first is I can hold headspace much more consistent. With normal expander ball dies you may as well just thread them in until they touch the shell holder, and you get what you get. It's not uncommon to see .003" or more difference in headspace case to case. With that expander ball removed you can keep headspace to around .001" variance with no other tricks. I do anneal my cases every time which also helps. The second reason for this setup, and the most relevent to you is the Lee necksizing die specifically can use different size mandrels. There are bushing dies out there that can do the same thing, but they are sizing the OD of your case neck, and unless you are also turning your necks, they won't be as consistent as the Lee necksizing die which forms to a mandrel on the ID of the neck. You can order these mandrels for cheap in .001" increments you specify. These mandrels also interchange over all cartridges of the same caliber as far as I know. There is some brass springback, so it isn't like if you use a .310" mandrel you will have .001" neck tension with a .311" bullet. If I recall the standard 30 caliber mandrel is .306", and that works fairly well with most cast bullets. I have them from .306" to .309", as well as the undersize one they sell as .3035". I normally use the .308", but it's nice to have options.

My theory on why the poor seating happens is because you are trying to seat a bullet into brass that is sized so small that you are yielding that brass. You are essentially trying to size that case neck with a mushy bit of lead with no support for accuracy at all. If brass is sized to a more reasonable size, you are not sizing that case, you are only pushing a bullet in, and the elastic nature is holding the bullet in place. All I know for sure is that when I size cases like this, it solves the problem.

Some other causes of fliers and possible cures.

inconsistent bullets - weight and visually sort bullets
inconsistent ignition (doesn't always show up on chronograph)- try different primers
gas checks falling off- anneal your gas checks
bullets seating inconsistent - modify your bullet seater plug to better fit *I'm assuming your plug fits those rather pointy bullets well*

[Chena]

Could the fault be with the rifle instead of your cast bullet loads? A thorough cleaning followed by an accuracy test using factory match ammunition might be in order.

[Shopdog]

In no particular order,three things that made some serious improvements....

Annealing.... not an end all by itself,what it allows is other testing for your cases without the pitfalls of case inconsistency. Sneaking up,or dialing in neck tension.

Neck tension..... "can" be a hero or zero. Yes,each barrel is it's own rule. Some folks have a hard time admitting but,there are chamberings.... more tolerant than others regarding tension. Only one way to find out. I start with .002,and .004" of interference. That usually is far enough apart to be distinguishable.... once there's a clear winner,then go a little each way of that. I turn custom Lyman spuds.

Again,depends on this rig's "window".... loaded round neck to chamber clearance. Like annealing, by itself it isn't a big hurdle.... it's effect however on other aspects is why it needs to be calc'd cause you might be turning case necks. Seating depth,powder burn rates,etc.

Good luck with your project.

[PopcornSutton]

This can cover a lot of ground. I'll throw in a few observations of mine. But let me start by saying, in short range (100-200 yards) jacketed benchrest, the groups being shot today is smaller than ever! Some are simply amazing, but they are happening regularly. So if you went to a National shoot, many are going to show up with the best built rifle money can buy. So if you are going to shoot against those guns, your gun must be up to the task. So let's assume you have a very capable rifle.

Reloading cast bullets are not as easy as jacketed, because dies are made for jacketed bullets. Lots have been said here already about dies. But before the dies, your brass must be right. Most will say for cast bullets, fit is everything. So your brass should be treated with care. I weight sort new brass, weight each one and cull the ones that are not in the average of others. The bad ones stand out. Neck turn them and use bushing dies. You need to turn the necks so the majority is cleaned up, going to a 100% cut is fine too. Get bushings that will give you .001 to .002 clearance in your chamber of your loaded round. With cast, you can neck size only quite a bit since the pressures are lower, but if the brass gets sticky you'll have to full length resize. Don't use a sizing die with an expander button pulling back thru a neck. Bushing sizing dies does it all in one stroke. In an example of 30 caliber, most size them to .310. Some seater dies won't take a bullet that big. Or, since heavier bullets are used, the OAL is more than the seater will take. Dies can be modified to a degree. Your gunsmith can make you a seater die with the chamber reamer that fits great and is in line.

Learn how to work up a load, and try different powders. When I started, I tried the powders listed in match results, and none worked well for me. But I had a lot of powders, and it's beneficial to try different ones. And work with seating depth, don't assume jamming or touching the lands will always work. It's amazing sometimes what .005 change in seating depth can do.

Lastly, in my opinion, all else being proper, bullets are the downfall of small groups. Gas checks have their own issues, seating them square is not as easy as you may think. Weight differences are a given, so cull them. But even doing that, you can weigh and measure and size but nothing can check the balance of the bullet. Measure your as-cast bullets, I'll bet a beer that it's not round. Yes sizing can make them round, but the metal is just moved, but not evenly. Balance is still the issue. Great bullets are a main reason jacketed benchrest shoots so small.

[Bloodman14]

Somewhere in the past, someone mentioned using hot glue or JB weld to fill the hollow cavity of Lee seating dies to fit the particular boolit by filling said cavity and placing the boolit into the filler nose first. The filler would cure and you have a custom noseshaped seating die. Because they are so cheap, you could have one for every mold you have.

[sloughfoot]

My loads are 150 grain M&P FN with 29 grains reloader 7 and 170 fn Lee with 31 grains of IMR 3031. I to seat and crimp in separate steps. I use all Lee dies

[justindad]

Since you mentioned seating…
1) My favorite expander plug is made by Redding, because they don’t truly use a flare. Where some others would create a bevel flare, the Redding creates more of an expanded cylinder that holds the bottom 1mm of the boolit concentric and parallel to the case. It can flare if you go deeper, but I don’t. I think other expanders have this too, but not all. I insert the boolit into this expanded cylinder by hand as squarely as I can.
2) My favorite seating die is made by Hornady. It has a loose sleeve that guides the boolit straight, encouraging a square seating of the boolit.
3) Crimp or deflare in a separate step from seating. Consistent brass length helps create consistent crimps.
4) But I only load for pistols, so maybe all that is meaningless to you :)
*
How concentric is your press ram to your dies?

[Pirate69]

Wow!!! Lots of great suggestions and extensive knowledge.

[charlie b]

When I load mine with 3031 the most accurate load is only 28gn. For a 210gn bullet that gets me just under 2000fps out of a 26" barrel.

Your 31gn load may be pushing the 170gn just a little too fast.

When I used the Lee 180gn bullet I found the nose was just a tad undersize for my bore.

[mnewcomb59]

I have found clean brass and powder coated bullets to have a lot of friction against each other. I have seen on the press, right after the other, where a plain PC bullet seats with great force and with noticable runout, then the same PC bullet with a little bit of tumble lube seats MUCH easier and straighter.

I would suggest lightly lubing your PC bullets with about 1/4 strength alox or 45-45-10 or lubing your inside case necks with diluted alox on a q-tip. For this job I use about 2 drops of alox in a shot glass that is filled 1/4 full with mineral spirits. With my softest lead PC HPs for 9mm and squeaky clean brass I have to either lube the bullet or the case to get the bullet seated square. Otherwise they seat cockeyed and squish themselves and seat under the extreme force - sometimes it feels like double or triple the force of a jacketed bullet.

[atr]

i do the bullet seating and case crimping as two completely separate operations.

yes !!!

[Screwbolts]

I agree with charlie b, completely! and your Re7 load is to hot for the 150 grain blue thingies! What barrel are you trying to get accuracy out of?

When I carry/hunt with my 308/7.62 Nato chambered 24" barrel mauser action rifle. My load is 25 gr- Re7 with a 158 gr NOE Boolit lubes with Simple Green.

If you are PC with an open HP how do you not get out of ballance Boolits by the uneven distribution of PC in HP cavity?

I use lube in lube groves and have no use whats so ever for any HP cast boolitz. My opinion!

Bottom line, if your blue thingies are out of balance it matters not how you seat them!

much great info in all above posts, Good Luck!

[sloughfoot]

I take time to tap dry clogged powder out of the hollow point cavity. The smallest group is the best group I got with 29 grains of reloader 7. My barrel is savage axis with 1/10” twist. I got noe expander plug yesterday as well
308079

[sloughfoot]

I weighed and sorted my bullets and selected those that fell within a half grain. I used my new NOE EXPANDER PLUG size .315x.311 brass all starline trimmed to uniform length and used the Lee factory crimp. I’m excited to try these tomorrow 308083308084308085