Gun: 280 AI - Mauser Action 26" BBL 1:10 Twist. Sporter weight (unknown manufacturer, no markings-stainless)
Used gun, builder unkown. Gunsmith checked and approved. Rifling clear and polished.

Gunsmith - "Headspace is correct, Nice quality built rifle, everything looks good, bedding is O.K. but I would have done it different"

Range Conditions: cloudy, very light wind. 100 Yards

Brass: Remington Fireformed
Powder: RL-22
Primer: Federal 210
Bullet: 140 GN Nosler Accubond
OAL: 3.360" (.02 off lands)

Load 1: 59 gn.
Load 2: 61 gn.
Load 3: 62 gn.

Most accurate and consistent load: 59 gn RL-22 (poor 2" group @ 100yrds)
Other loads were all over the place. Scope is tight, Trigger is clean and crisp at 3lbs.

Problems:
1. 2 small tears in case at shoulder and neck intersection (1-w/59 gn. and 1-w/ 61 gn.)
2. Flattened primers. No signs of elevated pressure. (Improper resizing?)
3. Poor, Poor groups. Parent loads shot as good or better (Winchester Supreme 140gn)

No signs of excessive pressure. Full length sizing dies adjusted per manufacturer (Lee).

I have loads made up to 64 gns RL-22 and Nosler Accubonds.

What do you guys think?

I never generaly obther trying different powders with bullets when they are innacurate but because I had a box of relatively expensive interbonds for my 06 I moved from RL22 to RL19 with no improvement. I then tried VVN150 and got 0.75" straight away.

My own inclination would be to try a slightly faster powder for the bullet weight (RL19 or N160) and move to a cheaper ballistic tip for accuracy testing.

Good luck

First, how old is the brass? They might need annealed if they have been sitting around a long time or have been fired a lot.
Some rifles hate boat tail bullets too. I would try the Hornady 139 gr bullet. I have had extreme accuracy with them.
I have never understood why so many companys make nothing but boat tails for hunting. They don't do a darned thing unless you are shooting super long range where the bullet transitions and flies below the speed of sound. Guys buy them because they are pretty I guess. They play hob with the length of the bearing surface the barrel needs for stability and longer, heavier bullets might be needed for a longer bearing surface.
It takes more load work and velocity changes to find what the boat tail likes and normally, they like a slower twist.
I always work a rifle with flat base bullets first.

Sounds like an odd chamber.

How did you fire-form the brass - was it in this rifle? When you close the bolt on a stock 280 can you feel a bit of crush - you should if the AI was chambered properly.

If it was my project I'd load-up some standard 280s with modest loads and see how they fire-formed. If everything was right I'd load the formed cases AFTER NECK SIZING ONLY and try again. The cracked shoulders makes it sounds like the shoulder has been moved too far during sizing and moves back just as far when shot. A properly adjusted die should just bump the shoulder enough so that the cartridge can be easily chambered. Any more than this and you're increasing headspace which isn't good for brass and if pushed far enough may also be hard on rifle and shooter.

If the chamber and rifle are in good shape, this should result in long brass life. If accuracy still sucks its either a lemon barrel/bedding or loose sight our nut behind the trigger.

BTW I don't think 2" at 100 yd is too bad.

I think the case problems are coming from my Full-Length Sizing. I am only going to neck size future cases and see.

Also, I am going to play with case length. I think I am a little short for this rifle's liking.

I agree that 2" groups are just fine for a hunting rifle. That was the best group it shot though. Others were way out there. I am looking for consistency rather it be 1", 2" or whatever.

Use new cases if you are not. Could be bad brass. Chamber might be headspaced on a 280Rem and not .004 short to get the crush fit on the shoulders. Gonna need to play with the die set up once you get them fire formed..

I F/L size mine to line everything up a bit for the first load.

Try H4831SC.Mine hated RL22 with a 140 Accubond. Groups were close to 3 inches. Switched powders only went to .3. Real nice.

I fireformed 280 Remington 140 gn Winchester Supremes and Remington 140 gn Core-Loks in the rifle.

I have a Jarrett 280 AI that I love. I have had it for 20 years and it has worn out two barrels and is now on it's third barrel. Here are a bunch of tricks I have used on load development with my AI over the years: I think your brass is the problem here, and possibly how you fireformed it. I no longer use a load with a bullet to fireform the case. I use 22-23 grains of bullseye with a quarter to a half square of toilet paper tamped on top of the powder to fireform. Point it at the ground and fire away. Yeah, I thought the gunsmith was crazy for suggesting it, but I'll be danged if it does not work great and you don't have the extra wear and tear on the barrel with a bullet flying down it...saves money and increases barrel life, gives a beautiful shoulder too. Watch out and go slow on the fireforming, as the bullseye loads will heat the barrel up quickly. I do NOT like Remington brass for the AI. For a number of years plain old WW nickel 280 brass worked wonderful! I am now using Norma brass ($$$) because I am turning my necks and the WW nickel brass would not do the trick here. I stay away from Federal brass as it was/is too soft and the higer AI pressures enlarged the primer pockets pronto. I love RL-22 in my 140 grain loads, but in previous configurations (read: barrels) it has loved IMR-4831 and, to an extent, IMR-4350. Seeing as how you are getting mediocre groups with the RL-22, why don't you try about 58.0 - 58.5 grains of 4350? That is a proven accuracy load in the 280 AI with 140 grain bullets. A number of years back I was having trouble getting a "good" load in one of the barrels. He suggested trying Winchester primers, as their cup was supposedly thicker....that did the trick in that particluar load...you may want to try the WLR's. I see that you are using 210's...try the 210 M's. The 280 AI also shows an increase in velocity and ACCURACY if you use magnum primers as well sometimes...try the 215M's but back off a tad on your powder weight. That might do the trick with slower burning RL-22 loads.

Other loads that have worked other than the 58-58.5 grains of 4350: 59.0 grains of 760 with 140 grain bullet, 62.0 grains of 7828 with the 140 grain bullet. I have shot up to 64 grains with 7828 in my rifle.

One last thing: You mentioned symptoms of high pressure I believe with the lower loads of RL-22..flattened primers, etc. The 280 AI typically shows its best stuff with loads closer to the max....that it was showing pressure problems with a lesser load does not surprise me. Take advantage of the AI case and find your accuaracy load on the faster end of the spectrum.

Just my two cents worth from fiddling with my AI for twenty years and bending Mr. Jarret's ear at times as well.

Good luck

One of the primary causes of poor accuracy is the bedding. What are your groups like? If they are round then it cound be the crown or a half dozen other things.

I would switch brass to WW and see if they tear.

As to the loads the Nosler #5 shows 63 grs of RL 22 as max with 140's and in general it seems like that data is hot.

This thread reminds me again why I don't like improved cartridges.

Savage you might be right on with the bedding problem. If so, then the "problem" would not be with an improved cartridge.

I thought of another thing after my last comment. How about your dies? It was heavily recommended by Jarrett and others that I use Redding dies. After doing so, I have since replaced all my RCBS and Hornady dies with Redding dies...no comparison in quality and concentricity.

The 280 AI can be a pain to fireform, but afterwards the results are worth it. You have a way more efficient cartridge than the 7mm mag and 99% of the velocity of the mag in a lighter more manuverable rifle with less muzzle blast, blah blah blah....great round.

Good luck Rogue!

quote:

Originally posted by Ramblin Rogue:
I fireformed 280 Remington 140 gn Winchester Supremes and Remington 140 gn Core-Loks in the rifle.

Hey RR, We were not apparently clear enough which caused you to mis-understand the question - so I'll try again.

List the individual "Steps" you went through in your Fire Forming operation.

1. I took Brand New Cases and...

Try moving the bullet out to .040 off and then work your way back in .005 at a time. You barrel might not like accubonds- my 250 AI doesn't(yet)- groups with the AB run twice as big as the same load with a BT-( the BT shoots from .4-.5 at 100) I haven't played with the seating depth yet and the shape is slightly different, so I do think I can close the gap somewhat- not that the AB groups are poor for deer. It is just that the rifle shoots almost anything else around .5 or less.

quote:

Originally posted by Hot Core:

quote:

Originally posted by Ramblin Rogue:
I fireformed 280 Remington 140 gn Winchester Supremes and Remington 140 gn Core-Loks in the rifle.

Hey RR, We were not apparently clear enough which caused you to mis-understand the question - so I'll try again.

List the individual "Steps" you went through in your Fire Forming operation.

1. I took Brand New Cases and...

It looks like to me he fireformed 280 Rem factory ammo.

Hot Core - As mentioned in my original post, I fireformed standard 280 rem 140 gn Winchester supremes at the range.
Steps:
1. Bought brand new cases.
2. Inserted a single round into the chamber.
3. Closed the bolt.
4. Pulled the trigger.
5. Waited a minute or so and repeated. ??

Hank H.-
Thank you for your help and knowledge. I am curretly using lee dies. I ordered a Redding neck sizer die and seating die last week. I hope that will help some. I also am starting to try IMR-4831. If that don't work I am going to try 4350. If that don't work I am going to try different seating depths with each powder. If that don't work I am going re-bed the rifle. If that don't work...

It is tuff not knowing anything about the
rifle's history. I am still having fun though.

I got it dialed in now.

I had a sneaking suspicion that I may have some bad fouling in the barrel that has not been removed with the brush and Barnes CR-10. Cleaned it thoroughly with JB and loading some IMR 4831 and RL-22.

63 gns RL-22, 140 gn Accubonds, Winchester nickel cases (Fire formed in rifle) Sub 1" @ 100yds - Consistent

58 gns - 58.5 gns IMR 4831, 140 gn Accubonds, Winchester nickel cases (Fire formed in rifle) Sub 1" @ 100yds - Consistent.

I am quite pleased. JB works!

Hey RR, Glad to see you are getting some nice accuracy.

However, that doesn't address the Shoulder Splits.

quote:

Originally posted by Ramblin Rogue:
Problems:
1. 2 small tears in case at shoulder and neck intersection...

This could be due to the Cases not being a good match with the Headspace in your rifle. Forming cases for an "AI" is not always a straight forward simple firing of a cartridge in the chamber.

But, rather than belabor the point, if you continue to have Neck Splits, send me a PM. If you don't have any more, enjoy the rifle.

Best of luck to you.

Hot Core -

I necked sized my cases this go around and only uses Winchester Nickel plated. No shoulder splits and no signs of high pressure.

I put a caliper to the fireformed cases I was going to load prior to neck sizing. All measured well. I called my gunsmith and again he said the headspace was correct. I (and my gunsmith) think the problem came from my full length resizing and/or just weak remington cases. I have shot upwards of 30 AI rounds with no other splits.

I really appreciate your offer to help, if I have anymore problems I will be sure to PM you. Thanks again.

quote:

Originally posted by Ramblin Rogue:
...I (and my gunsmith) think the problem came from my full length resizing and/or just weak remington cases. I have shot upwards of 30 AI rounds with no other splits. ....

Hey RR, There you go. I'd of guessed the Full Length Resizing might have been just a bit too much and is where I was headed all along.

I prefer to Partial-Full Length Resize(P-FLR) so there is just a bit of resistance as the Bolt closes on the Case. But, it sounds like you have it whipped now.

If it begins happening to you again, you might try running a 30cal Expander into your "new" 280Rem Cases and then use the 280AI Full Length Resizer to bring them down so they create a "Crush Fit" for you.

Best of luck with the new rifle.