Handloading a .280 AI

[Mtnhunter1]

Nothing wrong with FF 280 brass, works quite well!
IMR-4831 & 7828 are good choices for the A.I. for the 140-160gr range.

 

[eoperator]

7828, 4831, or RL22 with the 160s should get you around 2900fps. That'll make short work of just any game you encounter.

IMR7977 and RL26 should shine too. My experience is almost exclusively with Hammers and for some reason they prefer the slower burn curve of RL26 over RL23 in my very limited testing

Would you mind giving your recipe with hammers? I have a 24" 1-8 280ai that should be finished next week. Going to try 155 hammer hunters and absolute's.

 

[MThuntr]

Would you mind giving your recipe with hammers? I have a 24" 1-8 280ai that should be finished next week. Going to try 155 hammer hunters and absolute's.

I'm using 143s a per recommendations by Steve of Hammer Bullets. I'm at 62.5 grains of RL26 with Fed215M. I was running 60.5grains of 7828SSC which was the exact same as 4831SC both produced 3050fps give or take.

The guys over on the Hammer Forums may offer better info but I'd wager 60gr of RL26 would be max for 155s

Also it sounds weird but multiple shooters are using Lee Factory Crimp dies (there are directions on the Hammer Forum) and Steve almost always recommends magnum primers. My load development did not include the crimp die but I'll experiment later.

 

[williaada]

Can you explain why the use of magnum primers instead of large rifle primers?

 

[Addicting]

Can you explain why the use of magnum primers instead of large rifle primers?

You can use either. The bullet manufacturer recommended using the mag primers in everything when I talked with him. Part of it is his bullets are longer than equal weight lead. The Mag primer sort of makes up for the 1/2 grain you loose in case capacity.

For example I can run a 180g Accubond over 3100fps. I can only run the 181g Hammer Hunter at 3039fps. That is solely due to case capacity being slightly reduced. I could fit the same amount of powder in if I wanted to run a more compressed load. Instead I just run a Mag primer in place of standard LR. The load has single digit ES and I shot a 1.5” group at 530 yards.

 

[manitou1]

You are running 180s at 3100 fps in a 280ai?

 

[MThuntr]

You are running 180s at 3100 fps in a 280ai?

Nope that looks like 300WinMag or similar

 

[marksjeep]

I also use magnum primers, at the recommendation of the gunsmith who did the chamber. Been using them in these AI loads for 7 years. Never had a problem. Using Barnes LRX however, not hammers in this one.

 

[Addicting]

You are running 180s at 3100 fps in a 280ai?

Nope it’s a 300 Sherman, it starts life as a 280ai piece of brass. I expanded it and fire form a new shoulder junction and angle. But for all intensive purposes the same concept applies across the board.

 

[Fire_9]

Can you explain why the use of magnum primers instead of large rifle primers?

There are a lot of guys that use mag primers no matter what cartridge they’re loading

 

[Brian in Montana]

Well... I actually loaded up a ladder test last night with 150gn Accubond LRs and H4831. I figure the first creature I might hunt with it is black bear and a 150gn would be plenty enough for a an MT bear. Plus, I'm just kind of interested in that bullet design, and pretty familiar with H4831, and Noslers published data indicates that combo as being "most accurate powder tested". I generally find Nosler's data to be pretty much spot on. Anyway, I have plenty other combinations to try if that one's not satisfactory. Or even if it is.

 

[ThunderNocked]

Well... I actually loaded up a ladder test last night with 150gn Accubond LRs and H4831. I figure the first creature I might hunt with it is black bear and a 150gn would be plenty enough for a an MT bear. Plus, I'm just kind of interested in that bullet design, and pretty familiar with H4831, and Noslers published data indicates that combo as being "most accurate powder tested". I generally find Nosler's data to be pretty much spot on. Anyway, I have plenty other combinations to try if that one's not satisfactory. Or even if it is.

how did this first ladder turn out?
my Double Broomed Kimber 280AI Build is supposed to be all finished by the end of the month. I'll be starting with factory loads but am watching these 280AI threads as I'm hoping to reload later this year when I run out of factory loads.

 

[Brian in Montana]

I keep meaning to update this thread. I'll have to look up some more specifics in my notes later, but I think I'm coming out with 2 pretty loads that will MOA or better. I have a bit more testing to though.

 

[ThunderNocked]

I keep meaning to update this thread. I'll have to look up some more specifics in my notes later, but I think I'm coming out with 2 pretty loads that will MOA or better. I have a bit more testing to though.

I'm definitely interested in your findings. Like I said - I've got a semi custom 280AI built off a Kimber Montana that should be getting finished soon. I'm shooting factory loads to start - bought 80 rounds of 162 grain ELD-X, 80 140 grain Ballistic Tip Nosler and 60 140 Grain Accubond. I figure shoot that this year, get used to the new rifle and get a good pile of brass to start reloading after this hunt season if any of them shoot good.
So I'm excited to see your notes! I'm brand new - never reloaded before.

 

[Brian in Montana]

I ran a ladder test (velocity) using H4831sc and the previously mentioned 150gn Nosler ABLRs - 12 rounds starting at 58.8 grains going up .2 with each shot with the highest charge being 61 grains. MV's got up to 2976fps. Flat spots were between 59.4 - 59.8gn and 60.6 - 61gn. There was also only a 4fps difference between 60.2 and 60.4gn (but this one didn't group so great). Based on the velocity data, I loaded 6 three-round test groups.

I find that if a load is not going to group, I can pretty much tell in 3 shots, but that's just the first step in a process of elimination. From that first round of 3 shot groups, 59.7gn and 60.7gn came out on top with .83" and .9" respectively. Next step is a 5-shot group.

Shooting off sandbags, I started off with the 59.7gn loads. Oddly, my very first shot of the day was about 2" high left of the rest of the group - 4 shots measured .63" with 3 shot practically in the same hole. I got no idea what happened on that first shot. Wasn't a clean barrel. I didn't feel like I flinched or threw it somehow, but I guess it's possible. 60.7gn, 5 shots come out .9" again with 3 holes touching.

My next step is to shoot another group with each, and also strap on the Magnetospeed again and get a basic 5-shot average of MV. From the ladder test, I anticipate 59.7 will be leaving the muzzle at about 2870fps and 60.7gn doing about 2975fps.

Gonna have to dial in and choose one over the other. If both continue to group about the same, I'll base it on the one with the better velocity data - extreme spreads, standard deviation, as well as average velocity.

Probably won't get to the range again until Friday, weather permitting. I'll keep posting results.

 

[ThunderNocked]

I ran a ladder test (velocity) using H4831sc and the previously mentioned 150gn Nosler ABLRs - 12 rounds starting at 58.8 grains going up .2 with each shot with the highest charge being 61 grains. MV's got up to 2976fps. Flat spots were between 59.4 - 59.8gn and 60.6 - 61gn. There was also only a 4fps difference between 60.2 and 60.4gn (but this one didn't group so great). Based on the velocity data, I loaded 6 three-round test groups.

I find that if a load is not going to group, I can pretty much tell in 3 shots, but that's just the first step in a process of elimination. From that first round of 3 shot groups, 59.7gn and 60.7gn came out on top with .83" and .9" respectively. Next step is a 5-shot group.

Shooting off sandbags, I started off with the 59.7gn loads. Oddly, my very first shot of the day was about 2" high left of the rest of the group - 4 shots measured .63" with 3 shot practically in the same hole. I got no idea what happened on that first shot. Wasn't a clean barrel. I didn't feel like I flinched or threw it somehow, but I guess it's possible. 60.7gn, 5 shots come out .9" again with 3 holes touching.

My next step is to shoot another group with each, and also strap on the Magnetospeed again and get a basic 5-shot average of MV. From the ladder test, I anticipate 59.7 will be leaving the muzzle at about 2870fps and 60.7gn doing about 2975fps.

Gonna have to dial in and choose one over the other. If both continue to group about the same, I'll base it on the one with the better velocity data - extreme spreads, standard deviation, as well as average velocity.

Probably won't get to the range again until Friday, weather permitting. I'll keep posting results.

awesome, thanks!

 

[Durango Mike]

I ran a ladder test (velocity) using H4831sc and the previously mentioned 150gn Nosler ABLRs - 12 rounds starting at 58.8 grains going up .2 with each shot with the highest charge being 61 grains. MV's got up to 2976fps. Flat spots were between 59.4 - 59.8gn and 60.6 - 61gn. There was also only a 4fps difference between 60.2 and 60.4gn (but this one didn't group so great). Based on the velocity data, I loaded 6 three-round test groups.

I find that if a load is not going to group, I can pretty much tell in 3 shots, but that's just the first step in a process of elimination. From that first round of 3 shot groups, 59.7gn and 60.7gn came out on top with .83" and .9" respectively. Next step is a 5-shot group.

Shooting off sandbags, I started off with the 59.7gn loads. Oddly, my very first shot of the day was about 2" high left of the rest of the group - 4 shots measured .63" with 3 shot practically in the same hole. I got no idea what happened on that first shot. Wasn't a clean barrel. I didn't feel like I flinched or threw it somehow, but I guess it's possible. 60.7gn, 5 shots come out .9" again with 3 holes touching.

My next step is to shoot another group with each, and also strap on the Magnetospeed again and get a basic 5-shot average of MV. From the ladder test, I anticipate 59.7 will be leaving the muzzle at about 2870fps and 60.7gn doing about 2975fps.

Gonna have to dial in and choose one over the other. If both continue to group about the same, I'll base it on the one with the better velocity data - extreme spreads, standard deviation, as well as average velocity.

Probably won't get to the range again until Friday, weather permitting. I'll keep posting results.

My best load is identical with Sirroco 150 and .5 less with the 150 ABLR, same group size.

 

[.270]

I found a good load with Rl26 and the 145 hammers in a kimber hunter. Scoots along a nice 3160. I tinkered with H4831sc and barnes 145 LRX but that kimber liked the hammers.

 

[Brian in Montana]

My best load is identical with Sirroco 150 and .5 less with the 150 ABLR, same group size.

You like those Scirocco IIs pretty good? I tried some 165s in my .308 a while back and couldn't get them to group at all. Left a lasting bad impression, but I know some folks swear by them.

 

[Durango Mike]

You like those Scirocco IIs pretty good? I tried some 165s in my .308 a while back and couldn't get them to group at all. Left a lasting bad impression, but I know some folks swear by them.

I only used them in the 280ai and a 7X57 and they were solid when pushed at or near the book max comfortably under MOA accuracy. Never used the 30's as I figured out how to make the Barnes shoot and then started with the Nosler accubond. Felt like getting back rifle shooting long range so acquired a 308 Begara to play with, mainly because I had several thousand Lake City 175 gr match left over from service rifle days. I even found several boxes of 168 Sierra Match King bullets from the early 70's (the box was dated 1972 and the price sticker was $9.89 per hundred).