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Can bullets cause inconsistent OAL?


Fretless

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On 3/5/2021 at 9:33 AM, Fretless said:

I'm using a Dillon Square Deal B, loading 38 special.  The first 1000 rounds I loaded used 105 grain coated bullets I picked up from Sportsman's Warehouse.  When I switched to some prelubed lead I was given, I noticed the OAL was off.  I started checking every cartridge, and they vary by as much as 4/100 from one to the next.  As far as I can tell, the bullets are the only variable that changed.  Is that possible?  Is there anything I should be doing to fix this until the coated bullets I ordered arrive?  Is there something on my loader I should be checking?

 

 

A couple of very simple things can affect overall length.  First, the flat nose of the cast bullets are not perfectly flat.  When checking them with a micrometer, I can rotate the cartridge and get slightly different readings.  Depending on where the jaws are.   Also, the bottoms of the cases may not be perfectly true.    Second, if the cases have not been uniformly trimmed, (which I don't do), you'll also see fluctuations in cartridge length.   

 

None of my guns are particularly case length sensitive, as long as I get them out past at least minimum.  Minor fluctuations like that don't seem to affect performance.  I like some recoil, so I'm not loading them down to where I don't feel any response.  So, if my loads measure 1.48 or 1.52, they seem to shoot the same.

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On 3/5/2021 at 1:42 PM, Kid Rich said:

Unless you are shooting an untuned 92 oal consistency should not be a problem. I can run 38 special with the 105 g and 357 magnums with a 158 g rnfp in the same rifle. Don't "fret" about things that do not matter.

kR

Do not matter!!??? What, KR? You’re from Maine. You’re supposed to say like this:?“It doan matta”!:P

 

Fretless - cast Bullets are run in a caster with (8) 2 cavity molds on them. There is probably that much difference in the molds themselves. Personally, I wouldn’t worry about it unless you were having feeding issues.  See you Saturday! 
 

Hugs!

Scarlett

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Thanks for all the good info.  Here's the follow-up:

 

I switched back to poly coated bullets this evening.  I made no adjustments whatsoever on the loader.  The fluctuation from one catridge to the next is now less than 5 thousandths. 

Let me say that again.  No changes in setup.  No adjustments on the loader.  With the lubed lead bullets cartridge lengths were fluctuating by as much as 4/100, and with the poly coated they are fluctuating less than 5/1000.  

Other than maybe the wax lube causing inconsistent grip/pressure between the bullet and the case, nothing else makes sense to explain the inconsistent OAL with the lubed lead bullets.

 

Tl/dr

I'll be using coated bullets from now on any time I can.

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There can be several reasons to use poly coated bullets.  Among them the most important to many loaders is much less need to clean lube out of bullet seating/crimping dies and firearm actions.

 

But to worry about up to 40 thousandths of OAL variance in a lubed-bullet cartridge that is about 1.600" long (2.5% of the cartridge length variance) when we are shooting at targets 10 yards away is wasting effort.  Now, if you put the two types of loads to a test that looks at mean and standard deviation in group size at 10 yards and you find poly bullets will shoot a STATISTICALLY SIGNIFICANT smaller group size in your guns, THEN you have a good decision point.   I find it always makes sense to measure the things that DO matter to your final result (a match score) than to the things that may be easy to measure.  Until you shoot some groups, you really don't know.

 

But to try to hold pistol ammo for speed work to the same kinds of OAL criteria some might use for precision benchrest or long range rifle work, is making silk purses out of sows ears.  Especially when you have no indication that the length variation affects the ability to hit steel targets.

 

Putting your effort into practice on shooting and transitions will pay off more handsomely.

 

good luck, GJ

 

 

 

 

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9 hours ago, Garrison Joe, SASS #60708 said:

 

But to try to hold pistol ammo for speed work to the same kinds of OAL criteria some might use for precision benchrest or long range rifle work, is making silk purses out of sows ears.  Especially when you have no indication that the length variation affects the ability to hit steel targets.

 

Putting your effort into practice on shooting and transitions will pay off more handsomely.

 

good luck, GJ

 

 

 

 

You make a point, but seem to be making a few assumptions, I'm sure with good intentions of allaying my stress and guiding a new shooter.

 

This is not exclusively pistol ammo, and the variance was causing nearly half the cartridges to be too short to risk in the rifle, not to mention adding the need for me to waste time measuring every cartridge.

 

The focus on practicing transitions/shooting is spot on.  That's exactly what my wife and I are doing.  Only eight matches into this sport we drove home with a pair of clean match tokens, while our stage times continue to drop.

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On 3/5/2021 at 1:42 PM, Kid Rich said:

Unless you are shooting an untuned 92 oal consistency should not be a problem. I can run 38 special with the 105 g and 357 magnums with a 158 g rnfp in the same rifle. Don't "fret" about things that do not matter.

kR

105's, 125's, & 158's seat at different depths on my 1050. No problem with the diff between 105 & 125. Big diff with the 158, as I learned painfully on the last stage of the SE Regional last year. 10 in the rifle on the last stage doesn't complement a clean match very well.  Extra diameter of the end of the bullet caused it to seat at 1.36 OAL. I'd like to learn some of these lessons the easy way if that ever becomes possible!

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57 minutes ago, Fretless said:

 

The focus on practicing transitions/shooting is spot on.  That's exactly what my wife and I are doing.  Only eight matches into this sport we drove home with a pair of clean match tokens, while our stage times continue to drop.

 

8 matches and you already shot clean? Nice going, it took me 2 full years.  While my overall stage times are getting shorter because I shoot with faster pards, my personal stage times are getting longer :blink: :ph34r: :lol:

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I should add that I truly appreciate all the advice I get here and at the range.  Even when people tell me something I already know, it helps me get better.  It is reinforcing, and helps me evaluate whether or not what I think I'm doing is what I am actually doing.

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1 hour ago, Max Payne said:

105's, 125's, & 158's seat at different depths on my 1050. No problem with the diff between 105 & 125. Big diff with the 158, as I learned painfully on the last stage of the SE Regional last year. 10 in the rifle on the last stage doesn't complement a clean match very well.  Extra diameter of the end of the bullet caused it to seat at 1.36 OAL. I'd like to learn some of these lessons the easy way if that ever becomes possible!

I'm curious Max, is the ogive on the 158 so much higher (towards nose) on bullet to cause seating to shorten that much?  Or, is your seating stem just accepting the nose of the 158 so much differently.

 

Incidentally Fretless, I load four different weight .358 coated bullets with same seating die/stem setting as well as same powder charge and crimp die setting.  The  105 seats at-1."5, 125-1.45", 135-1.65" (a round nose with slightly flattened point), and 147-1.5" (more of a cone shape with pointed nose).  The 135 and 147 have no "crimping groove" and are crimped wherever they are placed by seater.  Seems a bit odd to me that the 125 nets a slightly shorter OACL by 0.05 than 105, although they appear to be same configuration except 105 having shorter base.  They do differ in color but that should not affect coating thickness.  Of course, 0.05 is no big deal and all four shoot exceptionally with 5 shot groups of each being close enough not to worry if a bullet round change is needed within a magazine full.   147 is an excellent smooth shooting round but just not as economical to shoot.  I like to have certain colors to distinguish my normal rifle versus pistil loads, although all shoot fine in either. 

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3 hours ago, Fretless said:

You make a point, but seem to be making a few assumptions, I'm sure with good intentions of allaying my stress and guiding a new shooter.

 

This is not exclusively pistol ammo, and the variance was causing nearly half the cartridges to be too short to risk in the rifle, not to mention adding the need for me to waste time measuring every cartridge.

 

The focus on practicing transitions/shooting is spot on.  That's exactly what my wife and I are doing.  Only eight matches into this sport we drove home with a pair of clean match tokens, while our stage times continue to drop.

 

My solution may not be good for you.  But, here's what I do.  I load my .38 specials a little long.  For instance, Hodgdon data says that with Clays, a cartridge with a 125gr cast bullets should be 1.445".   My .38/357 '73's run really well with the cartridges a little longer, so I set them at 1.500".   Since my pistols are .38/357 there is no problem accommodating the slightly longer length.  I don't trim the cases, if there is a bit of a variance in length, there's no problem about them being too short, as I'm running them longer to start with.   To settle on the load, I run a few and test them out at the range for grouping, and to make sure Point of Impact is the same as Point of Aim.

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Am I missing something? Can't the seating die be adjusted when using different bullets to get the overall length you want. I understand that when using the same bullet you can get variations in length but with completely different bullets adjustments are required.

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4 hours ago, Max Payne said:

105's, 125's, & 158's seat at different depths on my 1050. No problem with the diff between 105 & 125. Big diff with the 158, as I learned painfully on the last stage of the SE Regional last year. 10 in the rifle on the last stage doesn't complement a clean match very well.  Extra diameter of the end of the bullet caused it to seat at 1.36 OAL. I'd like to learn some of these lessons the easy way if that ever becomes possible!

I was referring to differences in OAL with the same weight bullet and same profile. Which should be no more than a few thousands of an inch. I don't know ANYONE that would NOT check their seating die when changing weight and/or profile of their bullets. I can run 105's, 125's, 147's and 158's that are properly seated, crimped and the proper length.

kR

I would certainly check the die before I started loading 158s after loading any of the tc profile bullets, not doing so could very well end up with bullets collapsing  back into the case resulting in failure to cycle.

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There has been mention of case trimming in reference to the OP a time or two.  Maybe I have been missing something thru the years but I do not think length of case will affect OAL of  38/357 cartridges.  Yes, it can affect crimp, lock-out die, bulging, and a few other things but don't think it is problem in this particular situation.  I am agreement to lube in seater or need to change seating stem for proper bullet shape..  Pitching of lube in seating will certainly led to some shorter over-all-lengths, BTDT.

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4 hours ago, Smokin Gator SASS #29736 said:

Am I missing something?

Yes.  The issue I was concerned with involved varying OALs while using only one type of bullet (prelubed lead truncated cone flat point).  I did not have this issue with coated bullets of the same shape and weight.

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As long as you have a good (not excessive) crimp you should have no problem. As has been said before lube buildup can result in bullets being seated deeper in the case. Usually occurs more with BP than with smokiless due to the nature of the lube. Easy way to clean the die if this occurs is take it out of the press, take it apart and dump very hot water thru it. Use pliers to hold it when you do that. Spray it with WD40 and then dry it real well.

kR

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