280AI range results

[Evilsports]

Morning folks. I'm working on a hunting load for a .280 AI. Was hoping I could get a bit of direction,. It took me 50-60 rounds to realize that the 168 VLD wanted to be jammed a bit in this barrel, but now that I found it I went back and retested some charge weights. Found a reasonable weight at 58.6gr. Thus far my BTO changes have been fairly coarse, and I haven't tried jamming any deeper than the .012" here. Would you say that it's worth the time to try and fine tune the BTO at that 58.6 charge weight? Also, how deep have you guys jammed without issues? I realize it's barrel dependant, just curious what others have ran into. Testing has been done at 100yds so wondering if it might be worth it to try this load at 200 & 300 before tuning BTO any more.

Thanks,
Kevin.

 

[Evilsports]

BTO measurement is gross and includes comparator die, I'm old fashioned and too cheap to buy a digital caliper.

 

[Seabeeken]

I dont hunt with vld Bullets, never will. I also have no need to jam. I work back starting .020 of jam when needed. If i were to use vld, id be length testing at 300 or more. My 280ai liked barnes, .050 off jam with either H-4831SC or Reloder 22 but thats just my rifle's preference.

 

[Bob Wright]

I wouldn't jam a hunting bullet due to "possible" extraction problems and dumping powder in your action. Now I'd have a bullet stuck in the leade too.
I found a sweet spot for the 168 at .090 off. Len Backus has a thread on the process from Berger.

 

[Evilsports]

I wouldn't jam a hunting bullet due to "possible" extraction problems and dumping powder in your action. Now I'd have a bullet stuck in the leade too.
I found a sweet spot for the 168 at .090 off. Len Backus has a thread on the process from Berger.

I'll look for the Backus thread. I tried making them shoot just kissing lands, .005 off, .010 off, .015 off, .050 off, .090 off, .130 off and they were all laughably bad. If Ihad more time and money I'd definitely put a finer point on my BTO increments, but the first group I shot at .012 in had 4 out of 5 into the same hole, with a half inch "flyer". I'm close to the end of my wits, brass, bullets, powder. etc..

 

[Deputy819]

just curious what others have ran into.

Mine shot best with the 168gr vld-h seated at .010" OTL (CBTO 3.831 as measured with the Hornady comparator), charge weight settled on was 59.2 gr H4831, Nosler brass, Federal GM210M primers for a muzzle-velocity average of 2839 fps.
I did all the development for it at 200 yards starting with seating depth first with the minimum charge for all depths tested followed by the Satterlee method for charge weight.
Your '58.6' looks pretty promising to me. Stretch it out a little further and see what happens.

 

[Evilsports]

Mine shot best with the 168gr vld-h seated at .010" OTL (CBTO 3.831 as measured with the Hornady comparator), charge weight settled on was 59.2 gr H4831, Nosler brass, Federal GM210M primers for a muzzle-velocity average of 2839 fps.
I did all the development for it at 200 yards starting with seating depth first with the minimum charge for all depths tested followed by the Satterlee method for charge weight.
Your '58.6' looks pretty promising to me. Stretch it out a little further and see what happens.

Thank you for the help. Unfortunately I'm an idiot. I had tried measuring my chamber by removing the ejector plunger and firing pin and then progressively seating a dummy shell incrementally deeper until it felt as though the resistance was gone.

I couldn't find a threaded 280 Ackley modified shell for an OAL gauge so this was going to be the next best thing.

I loaded another dummy shell long tonight and lubed the bullet. Crammed it in and closed the bolt. Took it out and it measured 0.083 longer than my other method. Repeated it with another dummy round and got the exact same BTO measurement.

Turns out my incremental method was flawed, or more accurately the way I did it was inaccurate.

Basically, I was running under the impression that my chamber was 0.083 shorter than it actually is. What I calculated as .012 jammed was actually .071 off the lands.

I have a 5/16 x 36tpi tap on order, should be in on Monday. I'll lathe up my own modifies brass and confirm my findings before I send any more down range.

I feel dumb but at the same time I'm glad that I'm not .012" jammed, and shooting decent groups.

Looking forward to seeing what this combo can do with a less confused operator behind the scope.

 

[Bob Wright]

I'll look for the Backus thread. I tried making them shoot just kissing lands, .005 off, .010 off, .015 off, .050 off, .090 off, .130 off and they were all laughably bad. If Ihad more time and money I'd definitely put a finer point on my BTO increments, but the first group I shot at .012 in had 4 out of 5 into the same hole, with a half inch "flyer". I'm close to the end of my wits, brass, bullets, powder. etc..

I understand. Try a different bullet. It's frustrating I know. You have hit most of the jumps. One of those should have grouped. I feel you know how to jump distance and it ain't working.
If your velocity is stable, there really isn't much more you can do but switch. Double check velo....

 

[Deputy819]

Looking forward to seeing what this combo can do

You're in the right 'ball park' as far as charge weight goes, for sure. After you get your modified case made and test some 'new depths' using the Berger method I'll bet you find a winner pretty quick. Let us know how it goes. Curious as to why you're using magnum primers?

 

[bamban]

ES,

I think I still have the tap to modify cases for the Hornady tool. Send me a email if you want me to modify one of your cases that been fireformed and resized to chamber.

[email protected]

I quit using the tool, I just size a brass, split the neck to the shoulder with Dremel cutoff. Clean up the sharp edges with jeweler file.

To use, pinch the split neck to get some grip on the bullet. Seat bullet long, push the test round into the chamber till it bottoms out. Push the test round from the muzzle with a wood dowel or cleaning rod.

When the case bottoms out on the shoulder the projectile resting on the land will be pushed back into the case.

Measure COL for reference. Carefully measure CBTO for reference.

Old school, it still works. Save that same bullet for that chamber.

 

[AZShooter]

My 284 Win shoots the 168 VLD approximately .010" into lands. Never had an issue with bullet removed from case.

With that small amount of engagement the bullet will not be stuck in the chamber unless there is insufficient neck tension. .002-.003" will hold the bullet in place. Had a 7 Rem mag that used .030" engagement with .003" neck tension with unturned necks that didn't have an issue either. Thinking that amount might not be the best for hunting, but it worked in my rifle.

As for figuring out where you are with the bullet and lands... I polish the seated bullet with fine steel wool. Carefully chamber cartridge by dropping it into chamber with barrel pointed towards floor or with a CRF place cartridge in the bolt face. Close bolt and carefully extract. If the bullet is engaging the lands you will see evenly spaced marks on the ogive area. Once you have the reference it is easy to use a competition die to move in or out to suit your needs.

 

[Evilsports]

Curious as to why you're using magnum primers?

Thanks for bringing this up. I don't have a good reason. I was guided in my reloading by an older fellow about a decade ago, whose advice I respected. He had suggested that I use magnums on marginal non-magnum loads on account of the potential for our hunting seasons to take place in cold weather. (Saskatchewan Canada). Apparently he felt as though the magnum primers provided some type of ignition edge in harsh conditions. Based on your comment though I've looked into it and it seems like I may have just adopted one of his reloading quirks that wasn't necessarily based on testing. In his defense, he likely adopted the practice framed in anecdotal advice as well.

I'll do some of my own testing for sure, it looks like the 30-06 case is typically more cooperative with non-mag primers in this powder weight window.

Thanks again. I love the fact that with the help of places like this, reloading errors can quickly be turned into learning.

Kevin.

 

[Deputy819]

Thanks again. I love the fact that with the help of places like this, reloading errors can quickly be turned into learning.

Oh, It's not necessarily an 'error'…..if it consistently works for you (and the load) then great. You're not running near max case fill with the charge weight range you're exploring or anything like that so I wouldn't think magnum primers would be 'needed'. Federal GM210M's worked just fine for mine. The load I mentioned consistently gave me SD/ES below 10.

 

[john k]

I'm not sure about COAL as I shoot a bullet that likes a jump. But it's possible to achieve faster loads if you have a slower powder. H4831sc is a very good powder for the AI. In my Ackley, when my bullet weight nears 170gr, it seems slower powders have better all around results for me. I know that was not the subject you asked about, but when I see the .280 Ackley, I can't get enough talking about fellow .280 Ackley shooters and their feedback. Thanks