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.308 not grouping

A "hot load" in a 24" barrel doesn't necessarily mean that the powder is appropriate for a short barrel. A hot load simply means that there is enough powder to produce higher than typical pressure. A faster burn rate powder can produce less pressure while still burning faster. Imagine a graph showing a curve, a faster burn rate powder will result in the peak of that curve being further to left (pressure is produced sooner) than a slower burn rate powder.
 
After all the other suggestions are tried , check bolt nose to barrel clearance . Check both , barrel to chamber and bolt nose dia to barrel recess . Make sure no base screws are touching barrel .
Did you check bolt lug fit and both contact evenly ?
How tight did you install the barrel and was everything even and clean ?
Hope this makes sense , a little under the weather .
Gary
 
After all the other suggestions are tried , check bolt nose to barrel clearance . Check both , barrel to chamber and bolt nose dia to barrel recess . Make sure no base screws are touching barrel .
Did you check bolt lug fit and both contact evenly ?
How tight did you install the barrel and was everything even and clean ?
Hope this makes sense , a little under the weather .
Gary

As far as I know everything was good when the barrel was installed, the headspace and what not is a little outside my purview. My gun smith is damn good and has built several rifles for me that shoot 1/2” groups or better. I let him handle all the technical aspects. I just handle the final assembly and bedding.
 
As far as I know everything was good when the barrel was installed, the headspace and what not is a little outside my purview. My gun smith is damn good and has built several rifles for me that shoot 1/2” groups or better. I let him handle all the technical aspects. I just handle the final assembly and bedding.
Did he assemble the barrel ? If not did he have the receiver and bolt to take measurements ?
If the bolt nose is touching it'll throw a shot or 2 out . Easy check with Plastigauge and a magic marker
Each receiver is dif and if your smith is good he would have made the barrel fit , either the previous owners receiver OR yours .
 
Did he assemble the barrel ? If not did he have the receiver and bolt to take measurements ?
If the bolt nose is touching it'll throw a shot or 2 out . Easy check with Plastigauge and a magic marker
Each receiver is dif and if your smith is good he would have made the barrel fit , either the previous owners receiver OR yours .
Yeah, he cut the barrel to Length for the first customer but they changed their mind So they bought a new barrel and he gave me this barrel and fit it to my action
 
I shoot a 10 twist 308. I could not get 155s or 168s to group and it did as yours saying.

I moved to 175SMK and it came to life.

Mines a 22 inch.

175 smk and varget found the node
 
Well, as I stated in the thread earlier. I went out with it today to try some different loads. I also inleted the stock a little more last night to make sure I was clearing the barrel 100%.

I took out several different loads. A 178 grain Amax, 168 grain eld with a little faster powder, 150 grain with the faster powder, and a 165 grain ELD match.

Started out with the 168’s again just to see if my issue was the float. It was still throwing them all over the place.

Decided to try the 150s and see if lighter was the answer. It threw them all over the place.

Decided to try and go to the opposite end of the spectrum and throw the 178s down range.

Man am I stoked. It loves those 178s. I’m confident in saying this is a sub half minute gun off a good bench and sandbags, and tailored load.

The last group was a 5 shot group and I know that low flyer was because of me.


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Johnny,
Sounds like a good build to me and the bullet (168bgr ELD) is a good bullet for that caliber rifle. Now back to a basic....what powder and how much are you using to test with? For 100 yds I use 42 grs of RE 15 to get right at half inch or less in two different .308's made by two different manufacturers with different barrels on them (both 1:10). SO unless I missed it, clue us in on your precise load you've tested with. And BTW, some .308 like a jam while other hate it. So personally, if I were testing a new rifle, I'd be starting at least 10 thou out of the lands and once you get close in terms of reliable and consistent grouping, then move the bullet in or out 5 thou at a time and see what happens. Good luck and let us know how you make out.

Alex
 
Funny you mention that. Lol. See my above post. This thing likes the heavies.

Ya, thats where I was going with asking your twist rate yesterday. I didnt see your post before I posted trying the 175 smk's. I had a suspicion that was the problem.

My 10 twist will not shoot anything under 175gr. I havent tried any heavier. Stacks the 175 smk's to where I aint got a reason to try anything different.

Work on your seating depth and powder charge tinkering now, it should still tighten up some.
 
One thing I have learned about the 308. If you get one of the Heavy bullets like you have with the 178's to shoot. You can take one of the lighter bullets and use the same Powder Charge with the Lighter bullets.. It will most likely shoot good. With some to little Seating depth checking.
 
I wouldn’t go any heavier than the 168gr in a 1.10 twist short barrel.
Not knowing what powder your current load uses, I also wouldn’t recommend a faster powder. A change in CBTO May be all that’s neede to get you to .5 MOA.
 

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