bullet seating OAL

djs0110

djs0110

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I have a question and I hope this is the right place. I am trying to set the OAL of my reloads. I have a Hornaday OAL gauge and bullet comparator. I want to reload Sierra 168 gr. HPBT so I took 5 bullets and adjust the depth as per the instruction that came with the tools. I got an average of 2.336" at the lands. I have been shooting factory ammo (Hornaday 168 gr. HPBT) and it has been shooting really well. I measured those and got an average of 2.194". I check in the Lyman book and it tells me that the maximum length of 2.820". so I measure that and the Hornaday ammo is 2.805" so that fall within the spec. So my questions are:
How far over the maximum lenght can I go?
My rifle is second hand and I do not know the history, is there barrel wear?
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As long as there is some bearing surface holding the bullet in the case, you can go as long as you need to.

Optimal seating depth is typically relative to the dimensions of the chamber/throat in your rifle. Some bullets like to be jammed right into the rifling, whereas many like to have plenty of jump. Most factory guns are cut with really long throats to accomodate a wide variety of factory loadings. Optimal seating depth may be negated by the length of your magazine, in which case you may need to feed as a single shot to achieve maximum accuracy.
 
If you are chasing the rifling and loading single shot you can seat the bullet out as far as needed until the neck no longer holds it... or as long as the magazine is...
 
I loaded a couple of dummy rounds at 2.306" and they chamber in the rifle but don't fit in the magazine. I am not to worried about having a single shot, I would like to have the best accuracy.
 
Max Owner said:
I am guessing here.......................

Load up a few at the same length and try. Go longer/shorter by .005" and load up a few and try. You will find out what your rifle likes this way.
Click to expand...

Pretty much it.
On a new rifle, I usually start at .020" off the lands and take it from there.
As noted, some rifles are tremendously sensitive to this, while others shoot their best loading them as long as the magazine will allow.
I have three Tikka Varminters in .222, .223, and .260.
They grouped as well at maximum magazine length as they did longer ( single shot) or shorter........
Fortunately...they all shot well, regardless of OAL :D
 
The type of bullet may have some sensitivity as well. My 175s shoot best just off the lands. However, I've been playing with 155s that like to be actually shorter than the mag length.
 
I use the .005 step starting at that same length off the lands. I load about 5 shells at each length and and about 5 or more lengths.
When shooting, I start at the shorter length and work my way to the longer ones. All the while measuring group sizes and watching for signs of excessive pressure.

In my my Rem. 700 SPS-T, Sierra 168gr. are barely seated in the case neck.
Reloading manual lengths, I think, are to give you approximately factory figures.
 
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