Case Weight Ranges

[hounddawg]

Everything from Lake City to Lapua. Currently use LC (non sorted in any way) and Lapua in .223. Peterson and Lapua in .260 Rem. Alpha in 6mm Creedmoor. Hornady and Starline in 6.5 Grendel.

About 2 years ago when I started my road to developing match quality ammo I tried everything in the book and tested it including water volume and case weight.

I found the most important criteria for single digit SD's is the proper powder, primer and bullet combo. My case prep includes a neck trim and a light inside chamfer after each firing, cases are wet cleaned with SS pins. Before first firing I uniform all primer cups and when priming check for uniform primer seating between .002 and .006 below case head as per US Army Marksmanship team standards. Powder for matches is weighed plus or minus .1 gns. When developing the load I go like to down to plus or minus .002 grams to find flat veloccity nodes .3 grains or larger so I don't have to sweat match loads charge weights being off a tad or minor changes in temperature

I have great reloads, now if I can just learn to read wind and mirage. Wind shifts in the middle of 20 round F Class matches kick my butt

[Bart B.]

Originally Posted by hounddawg

Powder for matches is weighed plus or minus .1 gns. When developing the load I go like to down to plus or minus .002 grams to find flat veloccity nodes .3 grains or larger so I don't have to sweat match loads charge weights being off a tad or minor changes in temperature

.002 gram equals .030865 grain. You have to cut powder particles apart to get such exact weights.

[Jimro]

Actually no, not when tested in real life. Using .001 and .003 neck tensions for .223 there was a 6 FPS difference on average, for the .243 only a 3 FPS difference, and for .308 a 2 FPS difference. The only real change was in the SD with .003 providing the best consistency

That's not surprising, the difference between 0.001 and 0.003" of interference fit is minimal on uniformed brass. When the primer goes bang, that's enough force to dislodge most bullets and jam them forward a bit from uncrimped brass. There just isn't much bullet hold on uncrimped bullets unless you add a neck sealant or experience cold soldering that bonds the bullet to brass.

Milspec cartridges can range from a few tens of pounds to several hundreds of pounds of bullet hold, to the point where competition shooters figured out that seating a match bullet a tad bit deeper in the case (breaking the bitumen seal) would give them better results as it uniformed up the bullet hold before a match.

Why any of that has anything to do with case weight ranges is beyond me. I know folks who sort cases religiously and shoot high scores, I know High Master's who say, "throw a match bullet on top of some powder and send it!" and keep their HM cards.

My advise, if you shoot benchrest then sort everything by every repeatable measurement you can. If you don't shoot benchrest, sorting by headstamp and year is probably just fine.

[hounddawg]

.002 gram equals .030865 grain. You have to cut powder particles apart to get such exact weights.

you are just a fountain of misinformation aren't you ?

The A&D FX scale reports to the nearest 1 milligram. Here is a video demonstrating how it really works with kernels of Varget weighing 1.5 milligrams https://www.autotrickler.com/accuracy.html

now I'll just put you back on ignore Bart

[scatterbrain]

Hounddawg, I have often wondered about the repeatability of my scales, they check weight perfect, but do they each time? How much improvement did you see when you started using this scale?

For Reloadron, jam the bullet into the lands if you want to see instant inprovement on you group size. Back in the 60's, young and dumb, I had a 22-250 that must of had a throat 1/2 the length of the barrel, I could just stake a bullet into a case and fire. The group size became 1/2 what I was getting. If I didn't shoot a chambered round I had to knock the bullet out with a cleaning rod. I have not tried this with any other rifle.

[Bart B.]

Originally Posted by Jimro

That's not surprising, the difference between 0.001 and 0.003" of interference fit is minimal on uniformed brass. When the primer goes bang, that's enough force to dislodge most bullets and jam them forward a bit from uncrimped brass. There just isn't much bullet hold on uncrimped bullets unless you add a neck sealant or experience cold soldering that bonds the bullet to brass.

Milspec cartridges can range from a few tens of pounds to several hundreds of pounds of bullet hold, to the point where competition shooters figured out that seating a match bullet a tad bit deeper in the case (breaking the bitumen seal) would give them better results as it uniformed up the bullet hold before a match.

Most bullet pull spec I have seen on MILSPEC rifle ammo is 60 pounds.

Once had to load 42 rounds of issued hand loaded match ammo to shoot 2 sighters and 20 record shots in a 1000 yard match. 20 had no powder and their bullets barely moved from primer firing, maybe a couple thousandths. The bullet pull forces on the remaining 18 rounds weighing about 44 grains (charge weight) more than others was about 7 pounds, about 6 pounds on the duds without powder as tested the next day. Cases were new 7.62 M118 match primed reloaded with IMR4320 and Sierra 190's.

Lyman 310 tong tool nutcrackers were oft times used to crack bullet sealant on military match ammo. Which often cut vertical stringing in half. Not legal in EIC matches, it altered the ammo.

[hounddawg]

How much improvement did you see when you started using this scale?

not that much honestly, what you are looking for is a flat node that is plus or minus 1 or 2 tenths so that you don't have to be that precise. I had been using a 1975 Redding beam scale with a couple of mods up until last winter

A perfect load is where one case can have 35.0 gns of powder, the next 35.1, and the third 34.9 and at 500 yards and greater have less than a .1 MOA vertical dispersion if shot from a test barrel in a machine rest. If you do the load development right a RCBS 750 or any .1 gn scale is good to go for matches. For developing the load though I use frog hair measurements. As UncleNick has told us , powder will change weight depending on moisture content and the same powder may have small changes from lot# to lot#. For anything greater than 400 or 500 a flat node is a must or variances in charge result in vertical dispersion

If you want a cheap backup scale get a Gempro 20 off Amazon or Ebay. It's only about .01 gns off from the A&D in accuracy and is every bit as precise when weighing charges. It is small and battery powered which makes it a pain to use but it is a very precise scale, it's repeatability is excellent

[Bart B.]

Originally Posted by hounddawg

A perfect load is where one case can have 35.0 gns of powder, the next 35.1, and the third 34.9 and at 500 yards and greater have less than a .1 MOA vertical dispersion if shot from a test barrel in a machine rest....

I applaud any bullet maker who bullets can get less than a half inch vertical spread at 500 yards and especially one inch at 1000 yards with a 2/10ths grain spread in charge weight across 3 rounds.

Do you have a tuning weight on the barrel?

What company makes bullets so perfectly balanced to have the exact same BC to do that? One 3 shot series after another five times for statistical significance.

[hounddawg]

light gun match record for 5 shot groups at 1000 yards is 1.087" or about .1 MOA. 5 perfect loads shot with perfect form and perfect wind reading plus a good dose of pure T outhouse luck

https://internationalbenchrest.com/r...longrange-1000

[Bart B.]

Originally Posted by hounddawg

light gun match record for 5 shot groups at 1000 yards is 1.087" or about .1 MOA. 5 perfect loads shot with perfect form and perfect wind reading plus a good dose of pure T outhouse luck

https://internationalbenchrest.com/r...longrange-1000

Why were all the other groups shot with that load in matches larger?

The size of the biggest 5 shot group shot with the load used has to be considered to be realistic in any evaluation of its accuracy to be counted on.

All single few-shot group records are mostly luck. Same for six 10 shot group aggregate records whose biggest single group is several times larger than the smallest 5-shot group shot with the same load.

A dose of pure T outhouse luck should not be considered for realistic accuracy assesment of a load. The biggest groups shot best represent what can be expected some of the time. Average of several 5 or 10 shot groups is more realistic. Cherry pickin' the smallest to claim its value is popular. A 1.08 MOA group at 1000 is bigger than your perfect standard.

[cw308]

I enjoy reloading my own rounds , went through all the ways to create that thousand yard stare . I do sort my case brands , fire one brand per range trip . Making every case as exact as possible , meaning , sizing , trimming and seating primers . I double check my powder charges , first with the ChargeMaster 1500 and fine tune with the GemPro 250 , shoot the same lot of bullets . Never got into heating the brass or using a chronograph . Playing with new tools it nice up to a point .Got back into enjoying target shooting by limiting my crazyness. Once I found a accurate load , I now concentrate only on my shooting form . Untill I burn out this barrel , then it starts all over again .

[F. Guffey]

Once I found a accurate load , I now concentrate only on my shooting form . Untill I burn out this barrel , then it starts all over again .

Sounds great; I wonder if you have ever tried to measure neck tension with your neck tension measuring devise. I have never been bothered by that old thing about life being unfair. I have tension gages; none of my tension gages are marked off in 'tensions', all of my tension gages are marked off in pounds or deviation in thousandths. I also have strain gages, iso, iso.

My strain gages are dial indicators that are calibrated to read in pounds in big chunks. The first tension gage: I was working a set of tongs when I noticed this large clock looking dial with one hand/indicator. Again, no tension measurements, only in pounds as in thousands of pounds. For accuracy it was necessary to count the number of cables etc. etc. As the rigs got taller the number of cables increased.

Anyhow, I am the fan of bullet hold, because my gages do not measure in tensions I measure bullet hold in pounds. I have used interference fit and I have used crush fit, again, I have used presses with hydraulic gages to determine the amount of effort required to install sleeves; it never took long to get the readings up to thousands of pounds. I have never found a conversion that foes from tensions to pounds, I have never found a gage that measured in tensions; I have found reloadiung forums full of tensioners that are infatuated with the word tension.

F. Guffey

[F. Guffey]

And then? A company built a bullet seating devise that measures the amount of effort required to seat a bullet and no one noticed the effort required was in pounds. The bullet seating devise is hydraulic with a pressure gage calibrated in pounds.

No one noticed but there was no conversion for tensions to pounds. And then there are the grippers with the tensioners. Next we have the load cell-ers. they are reinventing bullet seating with load cells.

F. Guffey

[Jimro]

Most bullet pull spec I have seen on MILSPEC rifle ammo is 60 pounds.

Once had to load 42 rounds of issued hand loaded match ammo to shoot 2 sighters and 20 record shots in a 1000 yard match. 20 had no powder and their bullets barely moved from primer firing, maybe a couple thousandths. The bullet pull forces on the remaining 18 rounds weighing about 44 grains (charge weight) more than others was about 7 pounds, about 6 pounds on the duds without powder as tested the next day. Cases were new 7.62 M118 match primed reloaded with IMR4320 and Sierra 190's.

That makes sense for the following reasons. All the M118 primed brass I've used still has the bitumen in the mouth. A couple thousandths of jump forward is normal, especially if it's jumping into a match chamber. As far as having not statistical difference in pull weight, that makes sense because the bitumen is sticky/tacky and you waited for a day to test, letting the brass relax a bit. Disregard if you cleaned your neck sealant out with a solvent, then only the time and match chamber makes sense.

[Bart B.]

Those reloads were made a week before I picked them up on Friday to go to the match. Bullets and powder removed a week or more earlier. The Unit processed one 460 round M118 ammo can at a time.

I think my teammates had the loading room crew make them for me. But I won the match with 98-17V (old "C" target in 1971) losing 2 points barely out in the changing wind. A real life ball and dummy exercise.

[Bart B.]

Originally Posted by F. Guffey

Me? I want all the bullet hold I can get, there is no such thing as 'too much bullet hold'.

F. Guffey

If there is enough bulllet hold by case necks, the bullet will pull the case neck off the case then out the barrel with it. I have seen this caused by dissimilar metal bonding of 30-06 neck to bullet.

If you use this

http://www.corbins.com/hct-1.htm

you can increase bullet hold, a must to get the most grip.