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Old February 13, 2007, 09:49 PM   #1
Texas_XD
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Exceeding Max C.O.L?

Still new here folks so please bear with me. I did try using the search function but didn't quite find what I am looking for. Anyway, here goes nothing:

I recently bought a Stevens 200 in 7mm-08 and decided to try reloading my own once fired brass. Followed all the normal steps, including trimming the case etc. I loaded them to the max COL listed for the cartridge, 2.800; 45gr H414 and 139gr SST's but used WLR primers instead of Rems, hence the lighter powder load.
I decided to take a resized dented case I didn't feel safe reloading and make me a depth gage of sorts. Sliced vertically through neck into shoulder and insert bullet I'm using (SST), slip into mag, load as usual, careful ejection and measure. After doing this 10 times, resetting bullet each time after measuring, I constantly come up with 2.888 with an occasional .001 variance. So hopefully, that is enough info to work with or get us started and now to the questions:

1. Is this within SAAMI specs and safe to continue using this rifle?
Just get nervous when things don't agree when tampering with stuff that goes boom.

2. Is it okay to exceed the recommended Max COL by close to this amount?
I am wanting better than what I am getting now for accuracy, 1.2-1.4" groups (factory fodder), and would like to experiment with say 2.850 or .038 off the lands.
Got plenty of room in that blind mag, even fed the over-extended home-made depth gauge with some room to spare.

Anyway, sorry for the new guy questions, but I'd rather be safe than testing out my medical coverage.
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Old February 13, 2007, 11:09 PM   #2
Trapper L
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The COL is for a manufacturer, both ammo and firearm, to have a guide in which to build to a common goal. If the round will function thru the action, will stack in the magazine without binding, and does not bind when closing the bolt, it is just fine. I have bench guns that the round is so long that in order to unload a live round the bolt has to come out of the action. Most folks are not aware that COL is great tool in fine tuning a load for accuracy. Find a load that the rifle likes and then play with the COL to dial it in.
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Old February 13, 2007, 11:26 PM   #3
onlybrowning
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Make sure that you realize that when increasing COL, pressure will drop (all else being equal) and when decreasing COL, Pressure will increase, so be very careful to realize that when experimenting.
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Old February 13, 2007, 11:36 PM   #4
rwilson452
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tuning the OAL

Generally speaking, an OAL that is somewhere between .015 to .030 off the lands is where the sweet spot is. To repeat this a generalization. Some rifles work best righ tup against the lands and some like it way back. There is no way to know until you try it. Mostly I would suggest working in .005 steps. A word of warning. when seating against the lands it can cause pressure to jump excessively so don't use a max powder charge. It has been my observation that the max powder charge isn't the most accurate anyway. If you do find a sweet spot by extending the OAL you might want to go back and tweek the powder charge again as you have changed the case volume. You just might get a little more accuracy out of it.
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Old February 14, 2007, 08:50 AM   #5
Texas_XD
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Thanks guys! I appreciate the responses, my main concern was both the safety of myself and my new rifle. I happen to like all my fingers, eyes.. teeth etc.
I am trying to stay at least 3 gr. below any data I try till I get a handle on everything. So if it's a max of 55.9gr H414, I won't run above 52 on my trial loads. I looking to manage recoil and add accuracy, fully aware with lower charges I may be sacrificing vel.
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Old February 14, 2007, 09:26 AM   #6
rwilson452
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on the subject of powder I have found that larger cases are less sensitive to changes in powder charge than smaller ones. For example, with my 30-06 being off by .5 grains doesn't seem to matter. but as much as .2 grains can make a difference with a .223. I could theorize as to why but I won't. it would be no more than opinion. and you know what they say about opinions
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Old February 14, 2007, 02:06 PM   #7
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XD, before you go messing around with COL over what the book recommends, I would work up a load in .5 grain increments using the COL listed in the book. Then when you find the sweet spot, try lengthening the COL.

Using factory rounds as a basis to think you need a longer COL for your reloads is like shooting craps at LV. It COULD be that you DO need a longer COL, but you won't know that untill you have a good load to start with.
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