refining groups with ONE outlier

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  • Last Post 01 June 2012
TRKakaCatWhisperer posted this 29 January 2012

For a couple of years I've been working with a rifle that should give outstanding accuracy. Finally I replaced the bolts through the scope mounts and that hold the scope bases to the rail and SHAZAM! 8 five-shot groups that were all very good (first of the 9 groups I was a bit too casual in my shooting) except for ONE %^%# outlier in each group.

That suggests to me the load, as it occured randomly in each string.

OK, I'll go back to shooting groups of 5 slightly above and below this load, and try changing primers (perhaps inconsistant ignition).

I don't have a chronograph.

What else?

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LWesthoff posted this 01 June 2012

Couple of years ago I bought a pound of 5744. After using it for a few hundred rounds of .308W ammo, I traded it to a friend for some H4895. I did not have any special trouble with powder fouling, and I found it just about as accurate as my favorite Varget and H4895 loads. I got rid of it because I couldn't get it to meter accurately; I was constantly having to trickle a charge up, or dump a little back. Didn't figure it was any more accurate than other powders, and the aggravation it caused wasn't worth it.

Wes

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joeb33050 posted this 01 June 2012

I used maybe 5-6 pounds of 5744 in 308 and 45-70 and others and never got good reliable results. Many others did. If I understand, there are different lots/producers/formulas-it ain't all the same. Another secret solution that didn't, at least for me. joe b.

John Alexander wrote: billgaze wrote:

"Just asking here, but has anybody had a case of powder fouling with 5744?"

My first eight pounds of 5744 (in mid 1980) won some postal matches after well over 1,000 rounds without any cleaning. At the end of the season cleaned bore and groups were just the same as before cleaning.

The batch I have now results in hard powder fouling and ruins groups sometimes before the end of a ten shot group but for sure before twenty shots. That darned stuff is hard to get out. It was sometimes difficult to get a normal sized dry patch through as the first patch. Maybe I just got a bad batch but I have given up on it switched to other powders and no more hard to remove fouling.

I would be interested in the current experience of others with 5744.

John

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Tom Acheson posted this 31 May 2012

John,

While the list above is overly long and has the potential to discourage someone who thinks they must do all of those things, it does contain things worthy of consideration.

Bullet fit...is one the tests to tap a barrel into the throat and then hold the gun up to a light and look into the muzzle to see if any light is present around the bullet outer perimeter?

Someone once said “anyone can shoot a small 5-round group but shooting a good 10-round group is a whole different level of skill". It only takes one round to mess up a +5 round group.

The CBA National Record groups can be compared by looking at 5 and 10-round groups at 100-yards and 5 and 10-round groups at 200-yards. There are 28 group records and 14-pairings and there are only 4 comparisons that have a 10-round group that is less than a 2.00 ratio of the 5-round group. In other words in the majority of comparisons the 10-round group is over 2X the size of the 5-round group. Admittedly the shooter and gun are different in these comparisons but it does reveal what seems to be a believable trend.

Tom

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John Alexander posted this 31 May 2012

To bring the discussion back to TRK's original question:

"8 five-shot groups that were all very good (first of the 9 groups I was a bit too casual in my shooting) except for ONE %^%# outlier in each group."

It seems to me that without knowing the size of the five shot groups and the size of the same groups if the most unwelcome bullet hole is disregarded, the discussion has no chance of being helpful except wild random suggestions. Joeb asked this question back near the start but got no answer.

Most groups have one shot that makes the group bigger. It happens with the finest jacketed bullets. This is normal whether we call it a flier, outlier of something else it is not necessarily a sign that it is the type of thing we might imagine being cured by weighing or other sorting efforts.

If one shot in a group makes the group two or three times as big that may call for sorting bullets or other effort at uniformity. If the shot makes the group 30-60% bigger it may just be the natural distribution.

TRK has posed an interesting question but the key to an intelligent approach is the question are we looking at one distribution or more than one. To make a good guess the size of the eight groups with and without the worst shot in each is a start.

John

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John Alexander posted this 31 May 2012

"This is a sometimes charactorist of the new manufactured powder compared to MR5744, surplus with a different chemistry. My thought is that it is some reaction to the lube just in front of the chamber. As others have noted, a couple of strokes with a brass brush seems to remove it. WFIW, Ric

Ric,

You and I have different batches of powder. The fouling I get can not be removed by a couple of strokes of the brass brush. Ten strokes just smooth it a bit. Ed's Red is useless even when soaked. Some solvents (I think I used Carb out) will eventually get it out. I guess I will use it as fertilizer to avoid the temptation to try it again.

John

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RicinYakima posted this 31 May 2012

This is a sometimes charactorist of the new manufactured powder compared to MR5744, surplus with a different chemistry. My thought is that it is some reaction to the lube just in front of the chamber. As others have noted, a couple of strokes with a brass brush seems to remove it. WFIW, Ric

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John Alexander posted this 31 May 2012

billgaze wrote:

"Just asking here, but has anybody had a case of powder fouling with 5744?"

My first eight pounds of 5744 (in mid 1980) won some postal matches after well over 1,000 rounds without any cleaning. At the end of the season cleaned bore and groups were just the same as before cleaning.

The batch I have now results in hard powder fouling and ruins groups sometimes before the end of a ten shot group but for sure before twenty shots. That darned stuff is hard to get out. It was sometimes difficult to get a normal sized dry patch through as the first patch. Maybe I just got a bad batch but I have given up on it switched to other powders and no more hard to remove fouling.

I would be interested in the current experience of others with 5744.

John

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TRKakaCatWhisperer posted this 29 May 2012

A LOT of water has passed under the bridge since I first posted. I'm still very much in the persuit of accuracy.

First, by WEIGHING every bullet I've learned a lot about refining every aspect of casting bullets. Reducing 200-250 gr bullets to a variation of +/- 0.1 grain was a goal and with some moulds achieved. Took some time. But WEIGHING provided the feedback directly about variations in all the things that go into making the bullet.

Second, running (5 shot) groups across the range and wider, of recommended published charges got me NO WHERE in trying to find a good load for a known accurate rifle. Then in frustration, I picked the load with the least vertical dispersion and varied the seating depth. Groups went from crap to excellent to crap. BINGO!

3 shot groups are OK. I shoot 5 shot groups to get a little more info. I make the distinction that one should use the group to REJECT unworthy loads. Across the board when one shoots 5 to 7 groups (of whatever count) spaced closely together it is obvious when one compares the sequence of the patterns. REPITITION alone will verify that one particular group was representative of the population. And when it gets close, I'll repeat and do 5 five-shot groups.

It's typical from my observations to note that the shape of the group will typically go from scattered to horizontal to diagonal to vertiacal to scattared. Somewhere the vibrations are good and the size with be right-much small.

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onondaga posted this 29 May 2012

http://www.castbulletassoc.org/view_user.php?id=5098>billglaze:

Your rifle is talking to you.  5744 did that in one of my rifles. It stopped when I started pulling through my Hoppe's Bore Snake once after every 5 shot group. Then, groups actually tightened up.

Gary

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billglaze posted this 29 May 2012

Just asking here, but has anybody had a case of powder fouling with 5744? Out of a clean barrel, it's a great powder in my 6mm Remington 40XB, but after anywhere from 10 to 15 shots, the groups seem to open up, with an occasional bad flyer announcing that something's wrong. I clean the barrel, and all seems to return to normal. 5744 is the best grouping powder, (at 16 gr.) but it's kind of hard to figure out when the barrel is going to need cleaning. It'll be grouping at 1” to 1-1/4” and suddenly I'll get one out by 2” to 3". The word “frustration” doesn't adequately cover the emotion. I don't seem to have this problem with any other powders, or, if so, at least not so quickly. Looking for answers, because I like the powder.

In theory, there's no difference between theory and practice. In practice, there is. My fate is not entirely in Gods hands, if I have a weapon in mine.

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joeb33050 posted this 12 February 2012

Harp wrote: Getting a three eigths inch group and then a flier every time amd it's in a different order every time. Five shots. Temp average is 45. I don't believe I have a lube problem. Lars lube. I lube each nose with lee alox which stopped all leading. I will stop collet sizing a try to full length size and not set the shoulder back. The depth ot the firing pin crater is not very deep. I am using two rifles with hammer forge barrels and getting the same results.

I might be able to help if you were to tell us the group sizes for best 4 then 5 shot groups. With maybe 10 groups I could offer an opinion. joe b.

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Harp posted this 12 February 2012

Getting a three eigths inch group and then a flier every time amd it's in a different order every time. Five shots. Temp average is 45. I don't believe I have a lube problem. Lars lube. I lube each nose with lee alox which stopped all leading. I will stop collet sizing a try to full length size and not set the shoulder back. The depth ot the firing pin crater is not very deep. I am using two rifles with hammer forge barrels and getting the same results.

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runfiverun posted this 30 January 2012

use the minimum amount of lube necessary, and make sure it either all comes off at the muzzle or stays on all the way to the target. viscosity is the key.

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CB posted this 30 January 2012

I have great respect for Joe's work in trying to figure out the best practices for cast bullet shooting and make that knowledge available to anybody interested. His encyclopedic list above for improving accuracy includes about all the possible things you can do that sort of seem like they should improve accuracy. He has stopped short of such things as sprinkling holy water on the muzzle but has included about everything else anybody could think of. To be fair, he has expressed doubt about some of them.

However, the list is too long to provide effective advice to someone trying to reduce his two inch groups. Many of the things on the list if done will waste a lot of time and are highly unlikely to improve accuracy at the two MOA level.

A much shorter list of maybe ten things to check in order of the likelihood that they will improve accuracy would be more helpful. Why don't we collectively see if we can come up with such a list from most likely to help to less likely to improve accuracy? I could start with nominating one thing. Make sure that the CB fits the throat/bore in a way that seals against blowby of gases.

John

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TRKakaCatWhisperer posted this 30 January 2012

Good suggestions, comments. I've polished the brass. Next to check length, deprime, neck size - etc etc.

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joeb33050 posted this 30 January 2012

If the question is about the group shape and size and flyers: The groups must be “in control", means that each shot in the group must be made from the same gun/load, meanss that there is one distribution of shots. The easiest and least precise method of assessing if the group is “in control” is to see if it is round. How round? How many shots? It ain't easy. We want to separate groups with random outliers, which are part of all groups, from groups with outliers that show that more than one distribution is involved. Outliers are to be expected, but seldom. Frequent outliers mean multiple distributions. What means “frequent"? It is a puzzlement. I think/hope that the answers lie in the groups that we shoot, if we find out how to extract the information. I'm working on it. joe b.

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joeb33050 posted this 30 January 2012

If the question is about how to increase accuracy: It seems to me that there is a progression of steps that one should use in the search for accuracy. With a rifle/load shooting 2” 100 yard groups, weight sorting primers probably isn't the correct next step. After a lot of input I ended up with this hierarchy of steps-from the book.

joe b

see attachment below

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Ken Campbell Iowa posted this 30 January 2012

onondaga wrote

some lubes and some barrels  are sensitive to time between shots ..i think something to do with barrel conditioning...whatever that covers.

might be interesting to fire a 20 shot group and have someone yell “fire ” about every 30 seconds.

not the same as --warming the barrel -- else it wouldnt happen on 105 degree days ...

some shooter a few years ago wrote  ” flyers keep ruining my groups  ”   (g)

chaos my butt, we gotta blame this on SOMETHING !     ken          

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runfiverun posted this 30 January 2012

random unexplained flyers. either you need to weight sort. or you are getting lube purge. or your lube is coming off the boolits in uneven chunks.

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CB posted this 30 January 2012

I like Ric's method of having five shot groups and also ten or 25 or ? shot groups at the same time.

Arguing whether 3, 5, or ten shot groups are better is silly (unless you are naive enough to only look at one group) because it is the total number of shots you shoot that is important, not the number of shots in any one group.

It is equally valid to shoot three ten shot groups, six five shot groups, or ten three shot groups. If you do all three and then compute the average of each type of group and then adjust the three and ten shot group averages to “equivalent” five shot groups with the well known adjustment factors which come from statistics (given in Joe Brennan's book.) You will find that all three methods give the about the same average.

Conversely you can convert the 3 and 5 shot averages to equivalent ten shot groups and find that the 3 and 5 shot averages properly adjusted to ten shot will give about the same equivalent ten shot group size as the average of the actual three shot groups.

The point is that you can get a pretty good indication of how accurate a rifle is by shooting 30 shots. It doesn't make any difference what the size of the individual groups are IF you count all the groups and they are adjusted right.

John

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