Case Capacity, Powder Position in the Case & Accuracy

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Last Post 15 October 2023

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Wm Cook posted this 07 October 2023

Since August I've been fighting a problem that has a powder, charge and bullet combination that'll agg in the .8's (my range, hand picked conditions, not implied in any manner that it could be replicated in match competition) some of the time but triple that other times with a production class .308 Savage.

When the load goes south it shoots as a pattern, not as an odd flier or two. And it can go from group to pattern quickly. And within the same range trip I've had it go South and come back North again before the end of the day. Its like every time I go to shoot a group I don't know if it'll be a group or a pattern. Best example I can give is its like the stem on your front rest isn't tight and the POI is wandering around. But bench equipment and bench practices are solid.

Below is an example which is typical of what I've seen many times these past three months. There were two other groups shot between the group on the left and the group on the right in the picture below. Ironically it just so happened that each group was shot with the 8th through 12th shot after barrel cleaning. The group on the left was the 7th group of the day and the group on the right was the 10th group of the day. Both are the same load shot in the same conditions. Side note: I load at the range in increments of 5 to 10 shots at a time as much to keep the barrel cool as it is to tweak the load.

Could it be the burn rate of the powder and the lay of the powder within the case?

All the powders I'm working with (fast to slow IMR4227, 5744, N130, 4198 and H4895) have a fill capacity in the 43% to 47% range with a 220 grain bullet running 1700 to 1780fps. All are extruded powders. I started using 5744 n the early spring after it showed some promise. I went back and bought a jug's worth of the same lot of powder. Far and away, the 5744 out shot all other powders that I've tried by a factor of 2. That said, powder is one of the few things left to tinker with.

If anyone has any thoughts on issues with the % of case capacity being used or the effect the powders position in the case many have on accuracy I would appreciate your thoughts. Thanks, Bill Cook.

A “Measured Response” is as effective as tongue lashing a stuck door.

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Qc Pistolero posted this 15 October 2023

Has anyone had any experience with using Dacron filler with the slower "fast" burning powders? 4227, 4198, 4895, 5744?

I've had some good results using Dacron with 4227 and 4198.Not always but I'd say more than 50% of times it was positive.Quite the contrary with 5744(BTW this powder is notorious for leaving unburnt granules;using mag primer and a heavy crimp will reduce them but it doesn't seem to affect accuracy)4895 I've never used a filler since I don't consider it a medium burning powder and I use a filler only with such.

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Wm Cook posted this 13 October 2023

in my earlier post mentioning dacron i referred to ShortTerm interest ... using fillers is probably just a dead end side tunnel down the rabbit hole ... but maybe if your groups improve from that it will be a clue ...

Ken I agree. Sometimes you just have to change something to make it better or worse to sort out the cause.

Being leery that mother nature likes to play tricks; If were me, I wouldn't celebrate until after a few more groups but so far so good.

Yeah, I know. Been down that path too often. Often a flush of success is like a bell ringing and they rush to the exit door. After second, thrid thoughts and as much as I hate to do it, I think I need to put together another round of test with the 5744 before I stop using the powder.

Attached is a target from a previous National.

Paul I would have paid $20 to be standing behind you with a spotting scope watching you and the flags while you were working through the sighter, then going on recored. The best statement back at the loading room would have been that you had it all planned out. That the sighter rounds were used for nothing more than to sort out all the variables before you went to record. First relay on Sunday mornings huh?

I think there must be someting having to do to powder granular size and how efficient it works. Take care all and thanks, Bill.

A “Measured Response” is as effective as tongue lashing a stuck door.

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CBA Member

Paul Pollard posted this 12 October 2023

Attached is a target from a previous National. It hangs on the loading room wall and makes me chuckle when I look at it. No two consecutive shots were close on the sighter, and I finally just decided to move up to the record target.

200 yd target

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John Alexander posted this 12 October 2023

Bill,

No doubt something changed on 8/21 and it looks like you have found it with Bud's suggestion. Congratulations.

Being leery that mother nature likes to play tricks; If were me, I wouldn't celebrate until after a few more groups but so far so good.

John

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Wm Cook posted this 12 October 2023

John, the flier was from another group. I shot groups at 19.6, 20.0 and 20.4. I wrote off the 20.4 out of hand because I had experience with bigger groups when I went up in powder. History favored the 19.6 and the 20.0g loads for accuracy.. Depending on how conditions were, sometimes 19.6 out shot the 20.0g and vice versa. In cases when the 19.6 went vertical, 20.0g brought it back just like it should. Sometimes 19.6 (approximately 1730fps) stuck like it should.

More powder than that (20.4 - 22.0) consistently got some groups.

If I were doing my part, the four and one's with the powder level in the case will out shoot the 4 and 1's (or 3 and 2"s) that were shot with the powder in an unbalanced condition. On a normal range trip I would have stayed in the 19.6 to 20.0 range and concentrated on the wind. I haven't had the confidence to lean into the wind since early August.

In hindsight I think what I was calling patterns were really 3 and 2's, or 2 and 3's. Shots that went out that I couldn't account for. I can deal with that for one range trip. But after 7 weeks of seeing the 2 and 3's or the 2, 2', and 1's was a bit too much.

Then there is the possibility that I am just looking to put closure to the problem and I should stick with 5744. Too bad the number of days left for me isn't as great as my appetite to dig deeper. I can see two fliers on all three of the groups on the left. So did the three groups on the right but they didn't go out as far. But my agg's for the first 17 groups shot with rounds laid on the bench were under MOA and the groups shot from the cartridge block (assuming powder upset condition) were over that by 1/2". In a four group match that's find by me. I can even tolerate a 2x group in match conditions because things happen. But over the course of 50 groups patterns develop.

In my mind I can see the formation of groups on all three of the right side targets. And I can see the three on the left close to or into an upset condition.

Then again, sometimes we can sell ourselves on most anything we want to believe.

John, I would appreciate your straight from the shoulder opinion.

A “Measured Response” is as effective as tongue lashing a stuck door.

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CBA Member

Ken Campbell Iowa posted this 12 October 2023

mr cook .. puffy dacron ... i just used only enough to hold the powder against the primer ...didn't weigh it ... i doubt the actual weight ... as far as Mass goes ... makes any difference, but the density is pretty light ... only enough to do the job for bench shooting .... not intended for 3 seasons of deer hunting ....

i think i bought my pack of dacron at walmart ... i just pull it out to thin it ... maybe * a wisp * of dacron describes it ... heh ... i always wondered if i was coating my barrels with melted plastic, but i shot hundreds of loads with no noticeable buildup ... my cleaning is just a couple passes of brushes with 4x steel wool ... if no lead ... and there never is ... then a slightly wet rag of essentially Eds Red ...

in my earlier post mentioning dacron i referred to ShortTerm interest ... using fillers is probably just a dead end side tunnel down the rabbit hole ... but maybe if your groups improve from that it will be a clue ...

also Larry Gipson has posted here a couple times mentioning these puffy fillers ... might do a search for those posts ...

ken

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CBA President

John Alexander posted this 12 October 2023

You didn't mention the two extra bullet holes in the lower right target. Just curious.

John

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Wm Cook posted this 12 October 2023

They are "as cast". I'm pretty illiterate when it comes to bumping bullets. Wanted to ask if anyone knew an article in FS that had some information about it. Not much recoil now that I finally learned how to take it. Coming from free recoil, 2 oz trigger to Production Class cast took some adjusting. Rattled my glasses a couple times until I figured out where the stock ended and my shoulder began.

Funny thing about the differences between loading from the loading block and loading from the bench with the 5744. From the loading block I think I could shoot groups all day long between 1.0" and 2.50". And outside of the flier now and then I think loading cartridges laying flat on the bench I could cut that by 40%. Again, as a disclaimer: my range, my conditions. Full home field advantage. Thanks again to everyone who kept me leaning into the problem. Bill.

A “Measured Response” is as effective as tongue lashing a stuck door.

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OU812 posted this 12 October 2023

I can send you some bullets to test. I had a custom mould made by accurate moulds and made a special bump die to bump rounds more round. I never tested this bullet because I never purchased barrel or rifle to shoot them in. You can see picture of bullet If you go to the gallery section of forum, click on bullets cartridges and more, picture 4 of 57. Bullet weighs about 180 grain...easier on shoulder.

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OU812 posted this 12 October 2023

Do you bump your bullets more round or do you shoot as cast. From my experience targets looks like as cast.

I bet that big bullet kicks shoulder pretty good

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RicinYakima posted this 12 October 2023

You are correct, as I went to University in 1966. I guess I am just an old out of the times fogey.

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Wm Cook posted this 12 October 2023

Sorry about not identifying that. The left ones were from the loading block and the right were from the bench. All four had fliers but the difference was that the loads out of the loading block went out further then the fliers off the bench. This is all new to me and I totally missed the obvious fact that a half case of powder could be kind of important. I might try the Dacron as an option. Do you remember how many grains you used? Thanks for the heads up on the sensitivity of the 4227.

A “Measured Response” is as effective as tongue lashing a stuck door.

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Ken Campbell Iowa posted this 12 October 2023

good stuff ... which targets are which position ... ?

in the short term, for research purposes, it would be interesting to try the puffy dacron filler trick with the 5744.

i have been having great luck in my 308 Tikka with 700X at short range ... ... but i think 1700+ fps for 200 yard shots are above it's range. wonder if blue dot or herco ... would be the Goldilocks powder ... nobody seems to use it tho ...

i haven't shot 4227 in a big case for years but I remember it as being location sensitive ... as was 2400 ... my best results with those 2 was with the puffy dacron ...that was with 280 rem and 30-06 trying for groups ... then i sold my soul to plinking and went to red dot, unique, and 700X ...

really enjoying your adventures ... please keep them up ... ken

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Wm Cook posted this 12 October 2023

Well......this is kind of embarrassing. But here goes.

The problem was self inflicted which (assuming you are a glass half full kind of person) was better to find out at my range than pulling out my hair at a match. The primary objective for the range trip today was to see if the 5744 powder position within the case had an effect on what I've been calling group v patterns. A secondary objective was to try a couple different powders and another bullet.

Conditions were interesting. Wind direction ran from 4:00 to 8:00 and wind velocity ran from a few moment of "A" to strong "C's". I break down wind velocity to alpha characters A, B, C, D. "A" being mild and "D" is with the flag tail held up there right tall and proud. So conditions were tough enough I could only run a couple, three shots then pick the rest. I haven't practiced holding off with shooting cast bullets with wind change because of the iffy "patterns" I was getting.

Now to take ownership for the self inflicted wound. Back in early August I put a cartridge block on my front rest. A cartridge block is elevated off the bench and is in close proximity to the loading port on the action. I've shot in this manner for decades and it helps me when I run (versus pick) a group. When conditions are right I try to put 5 down range as fast as I can. With jacketed PPC that's about 11 seconds. And most competitors were faster than me. We actually practiced how fast we could put 5 shots on record. The theory is that you're trying to shoot a decent aggregate not a tiny group. So when conditions are right you let it fly. I'm too new to know if that's common to cast accuracy.

Now the cartridge block holds the cartridge at about a 45 degree angle so its position so you can pick it as soon as your hand leaves the bolt (RB/RP).

With the angle of the cartridge as held in the block it tilted the case and it had the powder shifting toward the base of the bullet. Today the test groups shot with the cartridge block shot the same "patterns" I've been whining about. I switched back and forth between loading off the cartridge block and loading with the cartridges laying on the bench which had the powder pretty much level in the case.

The two groups on the left were loaded from the cartridge bloc and the powder was in the upset condition. The two on the right were loaded from the bench.

What I found was that 5447 is sensitive to its position in the case. Which opens up a whole new question about powder selection for the .308. None of the powders that I can see will even half fill the case. I would assume that some powders burn more efficiently than others. So when you are shooting honest "groups" and that group includes a flier (which doesn't disqualify it from being a group in my mind) is the flier caused by the powder position? John started a thread some months back with the title something like "What causes fliers". Never though about it since this circus I just waded through but powder combustion could maybe be a great excuse. Good shooters always have to have a couple, three canned excuses when a group is blown. They don't call it the wailing wall for nothing.

So the 5744 is going back on the shelf. The IMR 4227 looked promising and maybe it's shorter extruded power helps ignition. Its only a guess but with more surface area exposed it may burn more consistently? Knowledge about that is above my pay grade. Thanks to everyone, Bill.

A “Measured Response” is as effective as tongue lashing a stuck door.

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John Alexander posted this 11 October 2023

Geez Bill,

You have about everything covered. It sure looks like something changed 8/21, but what? Try putting a little Kroil on the bullet nose. They say the evil fairies that ride cast bullets and steer them away from the center of the group don't like the smell of Kroil.

When you get it figured out you may be able tell me why my rifle shot as well as it every has on Friday winning the little bore match with room to spare, then not winning a single aggregate when it counted on Saturday and Sunday at the nationals. Same everything except where the holes appeared.

John

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Mal in au posted this 11 October 2023

MP1886 G,day Tony,

I still shoot cast in my 2 .303s in the military matches,I still own a couple of .308s and plink cast for fun! We tried to get cast matches going at one of the clubs I am a member, some interest but soon faded ,not helped by the shortage of components here in OZ, primers are almost non existent ,faster powders the same! Rifle powder 2207(4198) 2208(Varget) can be had.Pistol shooters were resorting to buying shot shells and disassembling using the powder.Still waiting for the RAW HM1000x to turn up,.22 cal.at least I can still buy air and don’t need a primer!! Having to ration out components is a pain,my son and I have to share what we have left. Cheers from Sunny Adelaide SA (OZ). Mal.

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Bud Hyett posted this 11 October 2023

"I think what Ric means is that TRADITIONALLY and IN THE PAST this applied. I am inclined to think in our modern world it is no longer the case." - Do not confuse the scientist who collects data and interprets his findings with the politically motivated view of the project leader satisfying the sponsors and continuing the funding. The proper structure of a scientific project negates this result. In our time, many projects being funded by governmental agencies brings a strong political factor into the published data.

Like Ric, I am classically trained in the scientific process with additional training in Project Management (Master of Science in Project Management - a specialized MBA). One quickly learns the political influences within corporate structure are a part of any project planning. Our team reporting dealt with facts and data supporting our conclusions and basis for conclusions.

I now read all public reports of any project with a jaundiced view.

Farm boy from Illinois, living in the magical Pacific Northwest

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JeffinNZ posted this 11 October 2023

MP 1886,

There is no judgment or opinion in science. It deals with facts.

IMHO, Ric

I think what Ric means is that TRADITIONALLY and IN THE PAST this applied. I am inclined to think in our modern world it is no longer the case.

Cheers from New Zealand

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RicinYakima posted this 11 October 2023

MP 1886,

I trained, studied and spent the lasts 18 years of my working life as a environmental chemist.

There is no judgment or opinion in science. It deals with facts. Now if you know the facts, you can make better judgements and develop opinions. We use science to make art. Otherwise every picture would look the same.

IMHO, Ric

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MP1886 posted this 11 October 2023

From a Chinese artist:

There is so much science in art.

Perspective is science. Color theory is science. Proportion is science. Anatomy is science. And that’s just the basics. I’m not even talking about pigment making, canvas treatment. My oil painting studio back in art school smell like turpentine all year long.

And that is just traditional art. Digital art involves even more science. People literally write codes to create art.

I have been doing art for decades. And a big chunk of that time is used to learn “How” and “Why”. How to create a piece of art so it turns out the way I envisioned it in my head. Learn to interpret a piece of art so I understand the “why”.

Case Capacity, Powder Position in the Case & Accuracy

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