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Does bullet depth in case affect accuracy and/or performance?


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I have a Uberti 1873 Rifle and my wife has a Uberti 1873 Ladies & Youth Carbine.

For three years I have loaded 38's for both guns. I have been using 125 TCFP coated bullets w/ two crimp grooves.

I have loaded them in the past crimping in both the first groove (1.45" overall length) and in the second groove (1.5" overall length).

Both lengths cycle just fine through both of our guns, and have never had a round hang up and not cycle.

 

I am getting ready to reload for our rifles this year and started wondering if the depth in the casing effects accuracy and/or performance.

Your thoughts and knowledge would be appreciated. Thanks.

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Of all the rifles commonly used for sass the 1866/73 will be the least sensitive about OAL.  As far as performance and accuracy...  Theoretically a longer OAL should be more accurate because the bullet will be starting closer to rifling, but we are already talking about a 38 in a 357 mag chamber so for sass distances I would say no advantage one way or the other.  Seeing as both lengths work fine I personally would opt for the longer OAL length as this is closer to a 357 length and will mean less of the next cartridge has to be pushed back into the mag tube when the gun is cycled.    

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With our commonly very low pressure loads, there will be no noticeable difference between a .38 spl loaded to 1.45" or 1.50" OAL.   You might find the 1.45" load has slightly higher velocity if you chronographed both.  I have done the same kind of length tweaking in a 73 rifle and the shooter could not tell the difference in the "power" of the loads.   Just make sure your gun(s) feed them with no hangups.

 

And what's this "accuracy" you are concerned about?   At 7 yards, or even 15?   That you won't hit a 12" or 18" target?

 

Now, if you were tuning up a load for 100 yards shooting - THEN I could see you being concerned.

 

good luck, GJ

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8 minutes ago, Garrison Joe, SASS #60708 said:

And what's this "accuracy" you are concerned about?   At 7 yards, or even 15?   That you won't hit a 12" or 18" target?

I plead the fifth! LOL

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Check to see if the carbine will hold ten rounds of the longer cartridge. I normally load 38's at 1.45" for the wife's carbine with no issues.

Accidentally loaded some closer to 1.50" once and found out at a match that the 10th round wouldn't quite push all the way into the magazine.

I have since trimmed off the magazine spring to a minimum length I dare to and it will hold ten rounds of 1.50".

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If it makes any difference it can’t be much.  However, to satisfy your own curiosity you could put it on paper and see.

 

While GJ is right (and probably speaking just a little tongue-in-cheek), I like to know my rounds will hit where I’m aiming no matter the size or distance (within reason).

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I agree with all, IF any difference it is very minimal for our game.  If the slightest increase in groups shot bothers you mentally, go with what leaves less "doubt" in your shooting.  Personally, I would go with KIS method that is a Non Stop standard.  Example: your wife needs 1.45" for carbine then load that for all, including revolvers.  Just Keep It Simple in loading. 

I set the OAL seating for 105 then do not change seater for 125, 135, or 147.  All stays same in primer, charge, and seater set,  KIS.  Groups and velocity (which is checked) are tests that make for no mental hesitance.  I will sometimes separate loads to headstamp because often one feeds more flawless over another.

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WELL Heck.  Hate to be the harbinger of ill tidings.  However, I have never seen a 125Gr TCFP with TWO crimp grooves.  What you are mistaking for a lower crimp groove is actually intended as a receptacle for LUBE in uncoated bullets.  Not that you can't crimp in the grease groove, but it wasn't intended for that purpose.

 

Additionally, at our most common load levels for CAS gaming, at our extreme ranges (7 to 10 yards), you're definitely not going to see a measurable difference in the seating depth with regards accuracy or performance.  The larger difference will be observed whether you  manage to hold yer tongue right, or not. :rolleyes:

 

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44 minutes ago, Colorado Coffinmaker said:

 The larger difference will be observed whether you  manage to hold yer tongue right, or not. :rolleyes:

LOL. Or in my case keeping my eyes from crossed eyed.

The bullets I am using are coated Missouri Bullets Cowboy #2. It has two grooves, and the lower groove may be a lube groove. Your suggestion of keeping it simple between the 105 gr. bullets my wife shoots in her pistols and the 125 gr. in our rifles makes since, and I do not believe I would have to reset my die. In that case it would be the 1.45" OL. That also makes it a little easier for her to load in the 16" carbine.

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ive always thought that pushing the bullet farther into the case could increase the pressures but with our light loads most dont make much difference in the lengths we are using , i had some loose crimps that i hadnt noticed once upon a time , they got pushed in a bit before being shot , never even noticed the difference , but in a heavy load this might become an issue , 

 

the accuracy as noted was not a factor at our ranges , i have no idea how much more preasure might be generated by moving the bullet back into the case a bit [like maybe 1/4 inch] but im sure someone will mention it that knows a lot more than i do , 

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Generally speaking, the less empty space inside the cartridge the more consistent the rounds will be across a chronograph.  However, as virtually everyone here has already stated you won't really see a difference in your cowboy loads and it's not really worth worrying about.

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The short answer is "Yes"!   The longer answer has been addressed above.  I.e.:  To what extent depends on the bullet & charge.  

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