Ross Mk3 question 303 to 280

jaguar

jaguar

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As the title suggests, what would be necessary to alter a Ross .303 Mk3 to .280 Ross other than rebarrelling. I've read that this was the intent at the factory if the .280 cartridge could have been approved by the military. As described in print it sounded too easy to be true. Most obvious alterations that come to mind are around the bolt/extractor and the magazine. Even though the rim sizes are similar between the cartridges, I would expect the extractor may need adapting and also the magazine as the .280 is longer than the .303 (Would .280 cartridges even fit into a .303 mag, let alone feed out??). Especially interested if anyone has completed this task (hopefully on a clapped out sporter and not a nice original for sure).
Thoughts & Ideas welcome.
Cheers
Jaguar
 
The .303 magazine would be useless for a .280. The magazine assembly for the .280 would have to be created. It would be a good idea to compare a .303 receiver with a .280 receiver, and see what differences there are.
.280 ammunition and brass are not readily available. If something with similar ballistics to the .280 was desired, 7mm Rem. Mag. would be an option. But the magazine would still be an issue.
 
Hi

The MkIII action is almost there. The underside has two ribs(Not seen) that are 90 deg to the action (I wish I had Picts of the underside of the Ross MkIII action.). They are needed for the 303 mag. Remove the trigger guard and the 303 box mag. The underside of the 303 action would need the ribs removed. While I have never measured the dimensions. I believe without he ribs the underside of the action is .280 Ross ready. I recall the cartridge guides are angled for the .280 ross cartridge (Wish I had a pict).

The mag is very similar to the .280 M-10 (less the cut out for the 303, correct me if I am wrong) It is a solid bottom trigger guard that has a box mag with a follower like that of a mauser. There is allot of room in the mag area of the Ross once the 303 mag is gone. You can see the length is ok. Look at the wood that has been removed for the mag spring.
ross_cut.jpg


Picts of the action would be great, Anyone have any?

Peter
 
How easy is it to find a gunsmith who'll cut the proper threads into a .280 barrel? I wouldn't mind a ross or a p14 in .280.
 
If you were trying to build a .280 MkIII.....receivers are same length, but only detail differences. Use a triggerguard/magazine/carrier/floorplate assembly from an M-10. Boltheads are slightly different, but both will work with either calibre, and the extractor will also. What's the point, though? Likely a standard MkIII barrel could be bored out then sleeved down to .280, then the M-10 parts afro-engineered (screw on an original M-10 receiver -why not?) but in the end, you'd have buggered up two rifles, only to wind up with an expensive Bubbagun that the next buyer would try to feed .303's down-
 
Hi Rossguy.
Definitely don't want to bugger any rifles & finding a M-10 reciever unlikely. Future speculation on a bubba'd Mk3 with screwed barrel. Would envision having a 7mm blank turned to fit if reciever end was not a bushel of trouble to convert. Technically this would make it a .280 Halger but allows nice selection of bullets. Also would definitely mark barrel to correct cartridge. Ross sporters in .280 seem few & far between and priced quite dear, so was exploring this option.
Cheers
Jaguar
ps. It is my understanding that the 280 Hagler was based on the Ross .280 case only necked to fit standard 7mm bullets (.284 vs 288). If anyone knows of significant differences I'd like to know the details.
 
Skippy said:
How easy is it to find a gunsmith who'll cut the proper threads into a .280 barrel? I wouldn't mind a ross or a p14 in .280.
Click to expand...

I was going to re-barrel a Ross to 303 epps, I talked to Epps, they told me the p-14 has the same barrel thread. So...... all you need is a barrel and thread it to the same spec.

Anyone have the pitch (turns/inch) I know they are square threads.

Pete
 
Halger Magnum supposedly was identical to the .280 Ross, excepting that the pressure levels were scary.

I don't know where this idea of the .280 Ross having such a huge bore comes from. ALL the original cartridges in my collection (including a full box of King's Norton made for Gibbs) have a bullet between .283 and .285.

The only "fat" bullet I have been able to find is on the experimental .28 Ross cartridge (hstp: ROSS E), which is a .30-0'06 casing stretched out an extra quarter-inch and with a semi-rim. This critter DOES have a fat bullet, but all the .280 rounds I have seen use standard bullets.

You can make up .280 Ross brass from .300 Holland & Holland: FL size, trim, load, blow out. You may have to trim the belt just a tad. The rest of everything will blow out and flow out nicely. Or you could use one of these "Fat & Ugly" Magnums if you can afford the brass.

It was my understanding that the changeover from a .303 Mark III to a .280 Mark III would involve swapping the entire barrel, rear sight leaf and the magazine assembly. The Mark III stock is carved out enough that you should be able to get a commercial .280 magazine assembly into it.

Fellow I know is doing one in a 7mm Remington..... should be nice.
 
jaguar said:
....Ross sporters in .280 seem few & far between and priced quite dear, so was exploring this option...
Click to expand...

If you were to pay someone to do this conversion, it might be cheaper to buy an original Ross .280 sporting rifle.
 
Exactly the reason for the topic tiriaq. I'm trying to accumulate as much data on the subject as possible. Then verify data, plan, recheck, organize, then execute. Please don't picture bubba hovering over a couple of mint rifles with hacksaw, hammer, & file in hand. :eek: If it approaches the price of an original, then I'll be saving & shopping. The parts & bits will be saved for later.
Any additional data, still appreciated.
Cheers
Jaguar
 
.280 Ross bullet dia.

I've measured a few .280 Ross bullets (Kynoch) and to me they come out around .284-.285. My calipers arent the best however, so your results may vary. I also run .300 H+H brass through my RCBS .280 Ross dies with no problem. Havent got around to load development yet, just went with light 7m/m Rem Mag loads.
Geoff
 
Pblatzz said:
I was going to re-barrel a Ross to 303 epps, I talked to Epps, they told me the p-14 has the same barrel thread. So...... all you need is a barrel and thread it to the same spec.

Anyone have the pitch (turns/inch) I know they are square threads.

Pete
Click to expand...

Ref the threads on the barrel. They are not the same as the P-14, The p-14 allows the thread to be cut as there's lots of meat on the end of the barrel.

Pete
 
Hey Jaguar,
I just discovered this old thread...don't know how I missed it before .
Did you ever make up that 280 Ross?
With the help of the above threads I'm trying to use a Ross 303 Mag. for my 280 Ross...which didn't come with a magazine. It won't be a staggered box magazine , but at least I won't be shooting single shot .
I have a proper 280 receiver(it doesn't have the two 90 degree ribs mentioned by Pblatzz...like the 303 receiver has).
A 280 Ross cartridge fits into a 303 Ross mag. albeit a bit tight ....can someone guide me into the proper procedure to make the 280 fit ...before I start grinding willynilly ?
 
Wel, I'm going to modify that last paragraph a bit.... the 280 Ross will go into a 303 Ross magazine ...but won't go DOWN into the mag . Looks like quite a bit of modification to the follower and the do-hicky attached to the follower and spring ....
 
Surely by the time you've rounded up and/or purchased all the pieces you'd need to build a Bubbagun, fancy or not, you should be able to still find a decent original M-10 in .280 for around the same (approx) $1,000, and in the past, I've walked away from perhaps a dozen M-10's that had their butts bandsawed and rubber recoil pads added- $500 to $600 should buy one such rifle, then you can shoot to your heart's content and the value will still increase over time, unlike Bubbaguns....280 cases are commercially available down here south of the razorwire, but can you import? also .287" projectiles are here.
 
I have most of everything that I need...thanks to individuals on this forum...but I need a magazine to fit a 280.
I tried to build a mag, from strong sheet metal but my first attempt was unsuccessful .
I have a rusty 303 Ross mag that I am taking to my ice shanty, so that I can take it apart and clean up while waiting for the Walleyes to bite ....
I think the mag can be modified to fit, but was hoping someone had already accomplished this .
 
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