selecting cases

  • 4K Views
  • Last Post 29 August 2009
billwnr posted this 17 March 2007

I was out “testing” today as our BR cast rifle season starts next Saturday.  I started out selecting my cases with the ball mike choosing cases of the same neck thickness.

Then at the range I further selected ones by shooting groups and selecting the cases that hit in the group.  

I was left with a thought...how do I know when it hits slightly out.... is it the bullet, or is it the case.  Anyone else out there try to separate flyspecks from pepper?

Anyways.... it was a good way to spend the morning.  I do have my powdercharge and sight setting ready for next Saturday.  

Bill W

Attached Files

Order By: Standard | Newest | Votes
CB posted this 17 March 2007

Bill,

I'm not fer sure what yer talking about, but yer bullet hits the target, not the brass! :)

I tried the same thing you you just tried with my sloppy 308 Savage, and gave up on the idea, but of course a tight-neck custom BR rifle could be fussy. Still, as long as the cases has the same neck thickness, they should werk. My Jacketed BR buddy just neck turns and shoots matches, not worrying about one case or another. If you are loading the norm BR case, by just the gas check, don't worry at all about them. Cases are meant to hold a primer, powder, and the bullet by the gas check to go bang.  There are other more important forces in direct responsibility to accuracy.................Dan

Attached Files

billwnr posted this 18 March 2007

Dan, I was trying to account for the “unexplained flyers” that show up at the wrong time. I also played with harder rear bags and using the adjustments on the front rest to get the crosshairs in reasonably close alignment before squeezing the rear bag for final positioning.

Uniform neck thickness in the brass being shot seems to have an effect. I have two cases that are .001 thinner than the rest and they do impact at a slightly different spot.

This is why I was shooting my “candidates” to see how they performed.

My choice was either go shooting in the morning and focus on the insignificant..... or watch NCAA basketball. I chose shooting.

P.S.  More sand in the rear bag  did add some accuracy improvements.

Attached Files

CB posted this 18 March 2007

I agree with Dan to a point, I would stick with all of the same brand of brass, and some manufacturers brass seems to be better than others. I use strictly Lapua for this reason, and yes it did make a difference.

As for flyers, 2 things come to mind... Bullet Lube and Powder Charge. Of course the human factor can cause this as well.

I think consistency is the most important thing, whether it is powder charges or the shooter.

I personally weigh each charge (if I can) before each match. ( sometimes I don't have enough time and end up loading at the range and my performance shows it)

I use primers from the same lot, powder from the same lot.

I use only the bullets that have absolutely flat bases and small radius on the corner of the gas check.

Bullet lube... Boy this is an area that creates more disagreements than congress. I make my own because I can't buy what I think is good competition grade lube. I have tried many if not all, with the exception of White Label caranuba red* in competition.(* only because I just learned of it)

Some lubes are made to stay on the bullet, but if a chunk comes off in flight, then you have an out of balance bullet and thusly a flyer.

Some lubes are made to come off in flight, but are usually so soft that in the prep (bumping and loading) that some of it comes off on your hands. Also the soft lubes do not stay on the bullet in warmer temperatures and in a hot chamber end up melting in the throat.

Personally I want my bullet to completely spin the lube off immediately on muzzle exit, I don't want anything interfering with it's flight downrange.

Look carefully at your target, are there any specs of lube spatter on it? If so that may be the cause of the flyer.

When you clean your rifle, does it take a long time to clean? How many patches do you run down the barrel to get it clean.

What caliber are you shooting, 30 BR, 308, etc... If you are shooting a factory cartridge maybe the powder position or burn speed could be causing the flyers.

Attached Files

billwnr posted this 18 March 2007

Jeff, We're talking .30BR, the bullet is the NEI 72A and the lube is Veral's Blue something. I think I sniffed too much of it so I don't remember what the “something” is.

I had a big lube “splat” on a pistol target with my .429421's... but the NEI72A I shoot in BR competition takes so little lube it's not lube purging.

What I'm working on is so every single shot stays in the 10 ring with the BR gun. Every so often one sneaks out. So, I'm working on removing the variables so when this happens again it's reading the wind wrong.

The brain cells fired up again. I'm shooting LBT Blue for lube. I was curious how much lube went on these bullets and what the various components added to the weight mix. So, I weighed the bare bullet, the gas check and then afterwards to see how much lube was added per bullet. It might surprise you as its not the 0.1 grain of lube you hear people talk about. It's 0.4 grains.

A question for you Jeff, how do you verify your lube spins off when exiting the muzzle? Do you look at your targets, walk down the range..or what?

Attached Files

CB posted this 18 March 2007

Well if it is not evident on the target that is a good sign.

I look for lube spin off by shooting through a carboard tube about 3 foot long. I want the lube off completely within that time. After shooting I simply look down the tube. The tube is about 12” in diameter and is lined with butchers paper so the lube spatter will be easy to see. I mount (duct tape is great) this to my chrony tripod.

I will tell you that LBT Blue is designed to stay on the bullet. so what I wrote eariler would apply.

Attached Files

billwnr posted this 18 March 2007

I like the cardboard tube idea.

Attached Files

CB posted this 18 March 2007

Bill,

Uniform neck thickness in the brass being shot seems to have an effect. I have two cases that are .001 thinner than the rest and they do impact at a slightly different spot....Bill

You already answered yer question knowing a .001” neck thickness makes a performance difference in accuracy. You can measure that and you have control over that, so don't worry about yer cartridge necks.

I find flyers come from the bullet not seated perfectly in the throat. I can use any reasonable powder around the same burn rate and not get flyers. Your 72A bullet being a bore-ride needs to rest well from the lands on the nose at .300” (bore dia.) to your .314” over groove diameter ( I think you said?)

I've also found that LBT Blue can cause trouble in 100 and 200yrd rifle shooting. I know the MTL lube I use comes off at the muzzle because my chrono is covered with splattered chunks of lube. Bullet lube does you no good once the bullet leaves the muzzle. Some lube recipes add resin as a 'tacky' agent which isn't needed. I don't think hard lubes are needed, soft lubes are a lot easier to work with and I know soft lubes will fly off instantly.

Dan, I was trying to account for the “unexplained flyers” that show up at the wrong time. I also played with harder rear bags and using the adjustments on the front rest to get the crosshairs in reasonably close alignment before squeezing the rear bag for final positioning...Bill

Don't squeeze yer rear bag! That is a terrible bad habit. The rear bag should be packed hard with heavy sand (preferably) and as hard and stable as yer front rest. If the rear bag is soft and mushy and yer squeezing it, it ain't right. Any adjustment should come from yer front rest, as that is why it is made the way it is. Hope this helps ya..............Dan

Attached Files

CB posted this 26 August 2009

Bench Techniques

Good bench techniques and reading conditions will cure the 4 in a group one out situation.

Those that don't believe what I and others say on this are prone to repeat the Past. Selecting brass is not going to replace the missed condition and inadequate bench setup you started with.

The basics approach needs to be repeated over and over again.

Let it be said Let it be done. 

Stephen Perry

Angeles BR:fire

Attached Files

JSH posted this 27 August 2009

My .02. If you are shooting a 30BR, what are you using as a parent brass? 7BR, 6BR, or a 308/3006 case reformed? Are you neck turning any at all? Even if the 30BR barrel is chambered for say Lapua 6BR brass necked up, I would still just take enough off to clean them all up, back to the neck/shoulder junction. What kind of case prep are you doing? Flash holes primer pockets? Checking for flash holes being centered? Have you weighed any cases? then sorted them by lots. Loads. I have found very few powder/caliber combinations that shoot to BR standards that the case is not 85-compressed loads that shot well. Are you weighing bullets? Yes, I find it to be a PITA myself but may be well worth it. I mean if out of say 50, 29 weigh 165 grains, 10 weigh 161 grains then the rest all weigh + or minus a couple of the 39, there may be one fly in the ointment. Cocentricity It is harder if I would venture to say impossible to get a CB round down to the nuts like a FLGC. This is supposed to be a fun event, it is not work as long as any of the steps involved stay fun. When it becomes work, it seems one falters a bit on the end results.

I find the thoughts and ideas on the lube issue very interesting. I always figured a soft lube would stick on better and provide a better seal. Then it would fling off on it's way to the target. The more I thought about it I decided I was just splitting hairs. I don't know if I would call my home brewed lube match grade or not. But I like you Jeff never found a lube that I considered worth the $ for what I could make at home for less and do the same job. I ended up with FWFL and a bit of carnuba I just may have to give your lube a try along with some of Verals. jeff

Attached Files

JetMech posted this 27 August 2009

You guys are way outside my league, but one thing comes to mind when selecting cases. Given case length is equal, as well as neck thickness, then weighing cases might provide some benefit. A heavier case would indicate reduced capacity, which would effect pressure.

As far as lube spin-off, in BP shooting, we look for the lube star at the muzzle. You want some as an indication of sufficient lube, but not an excessive amount. FWIW.

Attached Files

billwnr posted this 27 August 2009

JSH wrote: My .02. If you are shooting a 30BR, what are you using as a parent brass? 7BR, 6BR, or a 308/3006 case reformed? Are you neck turning any at all? Even if the 30BR barrel is chambered for say Lapua 6BR brass necked up, I would still just take enough off to clean them all up, back to the neck/shoulder junction. What kind of case prep are you doing? Flash holes primer pockets? Checking for flash holes being centered? Have you weighed any cases? then sorted them by lots. Loads. I have found very few powder/caliber combinations that shoot to BR standards that the case is not 85-compressed loads that shot well. Are you weighing bullets? Yes, I find it to be a PITA myself but may be well worth it. I mean if out of say 50, 29 weigh 165 grains, 10 weigh 161 grains then the rest all weigh + or minus a couple of the 39, there may be one fly in the ointment. Cocentricity It is harder if I would venture to say impossible to get a CB round down to the nuts like a FLGC. This is supposed to be a fun event, it is not work as long as any of the steps involved stay fun. When it becomes work, it seems one falters a bit on the end results.

I find the thoughts and ideas on the lube issue very interesting. I always figured a soft lube would stick on better and provide a better seal. Then it would fling off on it's way to the target. The more I thought about it I decided I was just splitting hairs. I don't know if I would call my home brewed lube match grade or not. But I like you Jeff never found a lube that I considered worth the $ for what I could make at home for less and do the same job. I ended up with FWFL and a bit of carnuba I just may have to give your lube a try along with some of Verals. jeff

 

Interesting that this old dog rises up again.

 

Turned out that the problem was the throat was beginning to go and was finally discovered in early 2008.  The original barrel was shortened and rechambered using the original chambering and throating reamers and it now shoots like it previously did.

 

Now for the case and bullet questions.

 

The cases are the Lapua 6mmBR blown out to .30BR.  The usual case prep work is done; primer pocket uniforming, neck turning and holding the thicknesses to less than .00025 and eventually weight sorting them.   The way I hold the thickness to less than .00025 is one of two ways; one, to turn a larger quantity of cases and then sort them by neck thicknesses, or two, to turn the necks slowly on a smaller quantity of cases.  Just the holding of the tool and the friction of neck turning causes dimensional changes resulting in thinner finished neck thicknesses.   Uniform neck thicknesses result in uniform bullet tension which then leads (if the bullets are uniform also) to the shots going in the same hole.

 

Bullets:  A 90 lb batch of alloy is made and then cast into 3 lb ingots.  This results in the ingots being all the same mix.  Bullets are then cast up in a month long session over the winter when the garage is cool.  The bullets go thru multiple inspections during the casting, inspection, gas check seating, lubing and follow-on bump die reshaping of the bullets.

 

By this time the bullets are down to about 1600 in number.  This where they are all sorted by weight and put into individual trays holding 100 bullets.  Some of the trays (usually in the middle of the bell curve) are the the same bullet weight down to the tenth of the grain.  The rest of the trays may vary  .3 or .5 grains from the lightest to the heaviest bullet in the tray.

Hope this sheds some light and also provides some tips to other shooters.

Bill

Attached Files

JSH posted this 27 August 2009

Dollar Bill, I doubt I am even in a league,lol. I fooled with BR stuff just enough to know I was not going to have patience to deal with it, let alone $$$. We have several black smiths in the area and maybe one or two gun smiths, getting them to do anything in a timley fashion is some what challenging at times.

Look at what some of the LR black powder guys do when they shoot. Not a lot of difference really. What they both want in the end result is the same. I am getting nudges to try LR BP I just don't know if I have the time, energy or effort to do it at this time. Or do it as much as I would like too.

billwnr, I figured you had it under control from reading some of your other post;). I just had to ask because there was nothing noted regarding case prep.

I have ran across uh  several bench rest shooters.>. The shoot from the bench so..........lol. One gent did admit to neck turning, but really didn't know why. He just did it because he had heard or read that is what you should do. Mind you not a custom chamber of any sort, bone stock 700 308. I did make him a dozen cases from some LC match 06 brass. neck turned to match his chamber. It did shrink his groups a noticable amount, though he decided it was more work than he wanted to do.

jeff

Attached Files

billwnr posted this 28 August 2009

The first winter I cast BR quality bullets was a long one. Because of learning curve events I had about 140 hours invested in 160 good bullets. It took a while before I was able to make good bullets consistently. This was remedied by cranking the pot temp up high (725-750 degrees). Even if this temp seems too high it results in a low initial rejection rate. The molten alloy needs to be fluxed fairly often and the mould needs to be clean and hot also.

Most of the first month's production was scrapped out as there were too few good bullets. My thoughts about the lower temps (650 range) was to keep from causing the tin to separate out and also allow me to skim off zinc (if any). Anyways...way too many creased bullets or bullets with rounded bases.

Hot alloy (725 or so) and a hot mould just shy of frosting (use damp sponge to regulate temps) will result in separate casting sessions giving bullets of the same weight ranges.

After the “learning curve” my casting sessions to give a year's good bullets are in teh 40 hour total range. Lots less effort.

Attached Files

JSH posted this 28 August 2009

Bill I have had very similar results. I have pretty much went to straight WW for most shooting. I have a good supply of tin on hand. I only use it for a few moulds that I have had problems with filling out no matter what I have tried. I try to run the same temp as you mention. I do however have a lid or cover on my pot. It really helps keep the ehat in. Mater of fact the more lead I use the hotter it gets. So when I am down to a half or so I just refill. It is a 20lb Lee btw. I have found also that the head pressure or velocity that I get seems to fill most everything better, once the moulds are heated up to temp. I don't post up a whole lot. Your above post just confirms my findings, of course unless we are both wrong. LOL, I was wrong..........once. Jeff

Attached Files

CB posted this 29 August 2009

JSH

When I was a Yut, started at 12, casting for myself and my dad I used my mom's discarded Kenmore stainless chicken cooker. My mom contributed an aluminum pot cover that slipped over the cooker. As you said JSH the cover made a large difference in heating rate. I always kept probably 40 lb of lead in the pot. I liked to flux as much as Cast. I used parrafin, surfer wax if you are from So Cal, and it always flamed. I remember a few times when I added too much wax to the lead brew, the flame knocked on my tail bone. Didn't bother me much it was part of the casting. Bothered my mom as it filled the garage with smoke for a half hour. I still use parrafin and it flames but I use less. I now use shavings when I was a kid I used chunks of parrafin.

Stephen Perry

Angeles BR:fire

Attached Files

Close