7mm-08 specs
 

I boughta H&R barrel for my rifle in 7-08 and I am having accuracy problems., using factory ammo. I am new to reloading and I am loading up some loads for it. I did some checks on the chamber to find COL and it seems this chamber might be shorter than normal. Is there a certain spec, say from back of case to the lands and what is it for a 7-08. Someone told me on another board to check that but I havent got a response back. I used a spent case and put a bullet into it leaving it long and smoked the bullet with a lighter, chambered it and pulled it to check COL and the lands leave a mark on the bullet as well, it was 2.21 to the lands and COL was 2.83 on a 139 gr.

Specs are 2.8" for max COL. I have a short chambered 7mm-08 where I can only load to 2.74" and be .005 off the lands. But I like it that way.

If you can load a bullet to 2.83 COL and bearly touch the lands then its not short chambered.

with a 139 gr its touching lands at 2.83 . So where would you seat this bullet at to start.
with a 120 gr its touching lands at 2.88, where would you seat this bullet at to start.

.........Personally, I like to start my load development at .020" off the lands. If I find a promising load, I'll start tinkering with seating depth. I realize some folks like to start just on or just off the lands.....just the way I like to do it...

Personally. I would load at 2.8" for both to start out. find a load that is promising from different powder combos. After you find a good range of powder load, play with the COl a little. Load to 2.78, 2.8, and 2.82. See if one gets you where you want.

seems like I could wear a barell out before I find a good load. LOL
whats acceptable cool down between shots, is a warm barrell ok or does it need to get back to air temp
I have 40 rounds loaded in sets of 5, gonna do 5 shot groups

this barrell might have a problem.
For one my 120 gr measure .2815 and my 139s measure .282.
well when I seat the bullets .03 under, my 120's push in fine leaving no marks on a bullet I felt pened. the 139 feels tight being fed and is leaving a mark at one side of the bullet.
Like the area of the throat

I have checked and rechecked and come up with the same numbers. I did the cleaning rod method in the bore for COL and it matches up perfect with the other way.
2.83 for 139's
2.88 for 120's
even .05 off the 139,s leaves a mark on one side of the bullet
??????????

Hmm,thats not good. So your saying loading to 2.78", you see land marks on the side? Mossyoak33 was at my house one day with his 7mmmag, and I could feel some sort of imperfections in the throat using my stoney point tool.

Have you tried the split case method yet? Take a dremel and split the neck and tiny bit of the shoulders. Just enough tension to hold a bullet in place, and chamber and pull out and see?

Yep a 139 at 2.78 will leave marks on one side of the bullet right near the case neck and a 120 gr at 2.84 will not.

Explain the last part again, what is it you want me to look for, I did a spent case with a small crimp to check col, also marked the bullet, it does leave land marks but cleans one side of the bullet more.

Its kinda the same concept as the crimp. Except, the bullet can move but stay put when you "carefully" eject it. Sounds like you know where the lands are now. Honestly if I was you, I would just load to 2.75" and see what happens.

You sound like you maybe a lot like me and let things like this wrap you around the axle, and you get consumed. I know for years, I was consumed with runout and neck tension and neck wall thickness. I made reloading no fun. I kinda backed off, lowered my expectations for factory guns to 1MOA, even 1.5MOA for some guns and started shooting more.

could this mean my chamber and barrell are off center by .0005

Could mean a lot of things. Could mean reamer chatter, could be, you just seated the bullet slightly crooked and its nothing. I wouldn't get too wound up. Only way to tell if its off is to have it casted, and I don't think you want to pour that amound of money into it.

Pressed my 139,s in more, 2.753 and it still leaves a mark on one side of the bullet.
The marks are damn near the case.

Did some more checking, its not all the rounds doing it and the ones that do I spun the round and rechambered kept doing this and no matter what position it is in it hits in the same spot. so its the round itself that crooked somewhere. ?

If the round is crooked, you can tell by rollling the loaded brass and see if the bullet wobbles or neck wobbles. Doing it over a mirror is even better.

Yep did that and I have some wobbling, what Happened and how do I correct so It wont happen again, and will it affect accuracy, Im sure it will.

When you seat a bullet you want it to go in as straight as possible.

Here is what I have found. I found one culprit is slop in the shellholder. I put a post up on it a few years ago.
http://huntingnet.com/forum/reloadin...te-runout.html

Another thing I found is you can't correct runout much after its gone in more than 1/8" or less. So when you seat a bullet, you want to start right. So I rotate the case in the shellholder 1/3 at a time during seating. So you raise your ram until you feel the bullet slightly go in the case, lower the ram an inch or less, rotate another 1/3 turn, push the ram back up in the seater and seat another 1/8", or so, drop the ram and rotate another 1/3. It sounds like a lot but once you do it, it takes 5 sec.

I want to start posting some Youtube vids on this stuff.

Thanks for all the info, that makes a lot of sense.
Just got back from the range and it definately makes a difference. Every round that had some run out was a flyer.
I found two loads that were some what promising, got 2" groups out of them, much better than the 4" I was getting with everything else.
Didnt seem to like the 120 gr, this gun has a 1 in 10 twist I was hoping it would like 120 gr'ers.
is that the wrong twist for 120's ?

1 in 10 should be great for 120gr. I have 1 in 10 in my STW and it seems to like anything from 120 to 160gr. Not sure what my 7mm-08 has. My 7mmremmag is 1 in 9.25. All seem to handle 120's ok, but all loves 140gr best.

With those 120's try a different seating depth.

when testing loads do I need to load in 5 shot groups or 3 would be ok.
My reason asking is, you will never get a tighter pattern than your first 2 shots.

Is there a guage to check run out, and do you have a link

Yep, sinclair makes one, and RCBS makes one. Concentricity guage. http://www.sinclairintl.com/product/...tricity-Gauges

Once you go down this road, ain't no going back. :D

Thats what I love about metal work and reloading, your limit for precision is endless.

Here is how I load. I load 6 of each load. I shoot a group of three at 100 and another group after it cools down at 200.

Big isnt the runout issue where you usually recommend collet dies?

You know my MO. I went from not knowing what runout was and enjoying shooting, to hearing someone tell me I need to check for wobble, and I seen it, tried squaring my dies (waste of time IMO but I still do it), then changing shell holders, to buying a concentricity gauge, to the dreaded neck turning, then buying competition redding seating dies, to fireforming with cream of wheat, (this point I started making reloading no fun) then finally after all that for years and years, I started using the collet die along with floating my shellholder.

I should have skipped all the rest and just got a collet die and learned how to float my shell holder. It would have saved 1000's of rounds and a lot of head shaking.

LOL I listened to your advice and bought them right off the bat.

Just gonna butt in here and add my $.02 worth....STILL haven't heard from Hornady or Midway about the runout correcter I've ordered. Does anyone have any news on them?
I'm also a firm believer that runout is a group blower and am ANXIOUSLY awaiting the new piece of equipment...:confused0024:....

I still haven't seen any. I have been keeping my eyes peeled on them for ya. When I saw the first one, it didn't look that complicated, surpised they haven't hit the scene yet.

Thanks for the tip bigcuntry Loaded some up today spinning the case and seating a little at a time, worked much better. I cant tell you they have any runout at all, but they dont have any to see with the naked eye and I seated much closer to the lands with out anything touching.

Rolling them on a mirror, one should be able to spot any runout over .005"-.007". Most guns shoot fine with .005" or less.

Overbore calibers with long throats like weatherby's and RUM's don't like any runout over .003" I find. The closer you are able to load to teh lands the less runout is an issue. I don't know this for fact, just what I see from my experiements.