Jakeweb09
Well-Known Member
I'd shoot one or the other. I have shot many rounds of 180 hybrids at near the same velocity, then shoot 10 monos, switch Back to bergers and I'm 20fps slower
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280 AI weird groups??
- Thread starter Texis
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I have an 8 twist 280ai and only shoot copper Hammer bullets and it doesn't foul quickly. Easiest barrel to clean actually.
My guess is still on the proper bedding is your culprit.
Troutslayer2
Well-Known Member
- Joined
- May 28, 2010
- Messages
- 777
Both 280ai barrels I've had have been picky about fouling and shoot best when cleaned then just fouled a little. My consistency goes haywire after maybe 40-50 rounds.
Rflshootr
Well-Known Member
Too heavy of a firing pin spring can cause strange harmonics.
MagnumManiac
Well-Known Member
Two things standout here, stock is not bedded in the recoil lug, bed it tight everywhere except underneath the lug. The rifle should be difficult to remove the stock, if you want easy removal, put electrical tape on the sides and in front of the lug. I use tapered sided lugs for this.
Secondly, you have too much headspace, this changes ignition causing inconsistent start pressure. Try running .0015"-.002" and see if the groups stay tight.
The other notable thing, stop shooting cup and core bullets in the same fouled barrel as mono's.
Deep clean between using the two types.
Cheers.
Secondly, you have too much headspace, this changes ignition causing inconsistent start pressure. Try running .0015"-.002" and see if the groups stay tight.
The other notable thing, stop shooting cup and core bullets in the same fouled barrel as mono's.
Deep clean between using the two types.
Cheers.
Ldigio21
Well-Known Member
- Joined
- Dec 25, 2011
- Messages
- 64
Get a Hornady bullet comparator and measure CBTO. There are plenty of Youtube videos on this. Much more consistent than COAL. In my 280 AI with 23" barrel getting 2980 with 60 gr RE 26 with 160 gr Accubond. With 150 gr scirocco , 60.4 gr RE 26 3090 FPS. I can actually get better accuracy going faster than these loads but the group improvement doesn't seem with the extra pressure. Both those loads are consistently .5 MOA
AussieWriter
Well-Known Member
If it's not bedded, you have 2 mass produced illfitting surfaces being crushed together by a couple of bolts. Its a mechanical stress point.
Once it's bedded, if you move the seating depth, move it .005"-.006", not .010" which is too much movement with a light profiled barrel.
Once it's bedded, if you move the seating depth, move it .005"-.006", not .010" which is too much movement with a light profiled barrel.
I use a Whidden universal bushing for measuring at the ojive base to check the seating depth when loading. Very accurate setup, I recommend Whidden.
Correct, using the metplate (pointie end) as your measurement location yields inconsistent numbers. Sorry, I used the term "COAL" generically.
Correct, using the metplate (pointie end) as your measurement location yields inconsistent numbers. Sorry, I used the term "COAL" generically.
To answer an earlier question "before I changed the barrel"… the action came from a 25-06 that I owned for 40 years and a tack driver. It started to lose accuracy and I wanted more juice. I'm guessing it had well over 1,000 rounds on the original barrel.
When I installed the current barrel, the lugs blued square.
When I installed the current barrel, the lugs blued square.
Following
^^^^^ This.For sure bed the action to the stock and make sure the barrel is not in contact with the stock. Check barrel is now floated after your third shot, if not this could be issue.
Also, don't mix bullets during load development. Strip the barrel clean and pick a bullet and work with it. If it's not to your liking be SURE to strip the barrel clean before changing bullets. This is especially important with going between Mono/Cup-core type bullets. For instance- don't shoot a Barnes and a Berger during the same session. Ok to shoot a 168 Berger and then a 180 Berger as alloys are the same. I always clean my barrel if I'm switching to a different bullet mfg. I would say the majority of the time you're not getting a true indication of what your rifles doing when mixing projectiles during load development. Different alloys getting fouled into the barrel just change the barrel performance and consistency. JMO and experience.
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med358-boise
Well-Known Member
You might wish to read the following post. Yes, it is written with humor and there wasere a lot of "funning" back and forth, you will see that there is something to this.
Many people will not want to try this but you can also see more than a few have.
forums.accuratereloading.com
Many people will not want to try this but you can also see more than a few have.
