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 250 savage imp
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wolfpack
Junior Member

494 Posts

Posted - 02/03/2018 :  9:21:52 PM  Show Profile
Purchased a model 99 savage here on GB and while cleaning it this evening I noticed in very small letters "imp" right behind the 250 stamping. I doubt the seller ever noticed this as I have handled it several times before seeing it myself. Three questions, am I correct that factory 250 ammo can be fired in this and the case will fireform to the chamber? Will there be any headspace or accuracy problems with factory ammo? Last how do I determine what the shoulder angle is?




rufe-snow
Advanced Member

17865 Posts

Posted - 02/03/2018 :  10:26:46 PM  Show Profile
Your talking about 2 different cartridges. Don't get them confused. The "IMP", was used for the .22 Savage High Powder. The 250-3000 is a completely different cartridge.

Do a chamber cast to clear up the confusion. If somebody in the distant past, reamed a "IMP" chamber for 250-3000, because they couldn't get the brass. You would want to know about it. Firing a .257 bullet, through a .228 barrel could be very unhealthy.




EDIT #1,

Excuse my senior moment. Got 22 Savage High Powder, AKA, "IMP". Confused with the abbreviation of the word, "IMPROVED". Between the Super Bowl, Kardashians and the Democraps, my brain has rotted away.


Edited by - rufe-snow on 02/04/2018 11:14:02 AM
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wolfpack
Junior Member

494 Posts

Posted - 02/04/2018 :  07:34:41 AM  Show Profile
It is a later model (maybe 1970's) 99a that is factory stamped 250 savage that someone has taken a reamer to and it is stamped imp directly behind the 250 savage factory stamp. Chambers and cycles factory 250 ammo great.
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charliemeyer007
Advanced Member

USA
5503 Posts

Posted - 02/04/2018 :  07:59:58 AM  Show Profile
Since it will chamber a factory round, you could tie it to something and fire a round with a string on the trigger. Check that first case carefully.

If you are planning to reload for it you could fire form with a cast bullet load, I do all my fire forming with cast bullets. Some folks use pistol charge of fast powder and corn meal.

Depends on who did the work for head space issues. When re-cutting chambers there can be issues caused from using 2 different ones. The larger improved might not clean up everything from a poor job with the first one and accuracy could suffer.

Careful measurements and math will yield the angle.

https://4drentals.com/product/250-savage-ackley/

There are other improved 250 Savage.
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nononsense
Moderator

9998 Posts

Posted - 02/04/2018 :  08:01:22 AM  Show Profile
wolfpack,

quote:
am I correct that factory 250 ammo can be fired in this and the case will fireform to the chamber?


There are a couple of different variations on the 'imp' theme with cartridges, shoulder angles and fireforming.

Ackley Improved 'usually' includes a 40* shoulder and the chamber is cut to allow for fireforming factory ammunition safely. In your situation, the stamp is simply 'imp', leaving out any mention of Ackley. This could suggest that the shoulder angle has been cut to some angle other than the Ackley version, such as 30* maybe. But the gunsmith may not have been knowledgeable about such things and saved a minute or two by stamping 'imp' only.

quote:
Will there be any headspace or accuracy problems with factory ammo?


We are unable to answer this without having checked the chamber for shape, size and a proper headspace gauge. In Ackley chambers, factory ammunition has a good reputation for fireforming accuracy. But how can we tell without checking?

quote:
Last how do I determine what the shoulder angle is?


You need to cast the chamber to see and be able to measure the shoulder angle. You could also ask the original or previous owner for examples of cases fired in that rifle, then measure the shoulder.

Best of Luck with your project!









Edited by - nononsense on 02/04/2018 08:03:11 AM
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perry shooter
Advanced Member

17364 Posts

Posted - 02/04/2018 :  09:01:14 AM  Show Profile
I may be missing something here but it is easy to make a chamber larger than standard but also hard to make it smaller. I would try to fire a standard round and compare this after firing with another unfired round ymmv
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wolfpack
Junior Member

494 Posts

Posted - 02/04/2018 :  10:31:28 AM  Show Profile
Ok, more info. Just looked at rifle more closely and on the backend of barrel next to the receiver it is stamped 40' which should indicate a 40 degree improved chamber. It also has SP6 next to the 40' degree stamping. Anyone have an idea about the SP6 stamping? I would have thought it would have been stamped with AI or something similar. Just checked some other Savage rifles, two model 110 series both have sp6 stamped on them in the same location so it must be some type of Savage proof.

Edited by - wolfpack on 02/04/2018 12:51:56 PM
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Hangfire
Advanced Member

3095 Posts

Posted - 02/04/2018 :  1:40:16 PM  Show Profile
quote:
Originally posted by wolfpack

Ok, more info. Just looked at rifle more closely and on the backend of barrel next to the receiver it is stamped 40' which should indicate a 40 degree improved chamber. It also has SP6 next to the 40' degree stamping. Anyone have an idea about the SP6 stamping? I would have thought it would have been stamped with AI or something similar. Just checked some other Savage rifles, two model 110 series both have sp6 stamped on them in the same location so it must be some type of Savage proof.



Found this comment on SP6-

__________________________________________

sharpshooter
10-26-2011, 07:27 PM
If you talked with one of the guys in customer service you'll find they know less about the guns than you do. Their training only goes so far.
The proof mark... and yes they all have a proof mark, is a stamped SP and a number(example: SP7) The SP means "Savage Proof", the number denotes the person who actually did the proof firing. Proofers have a number and a stamp assigned to them.
Another mark usually visible,(example: A21) is the person who function tested the rifle after assembly.
All barrels will have a caliber code stamped somewhere close the nut, and on the bottom of the receiver between the lug and front action screw hole.
Example: M,=.223. Any letter with a circle around it indicates stainless steel. These are stamped by the person installing the barrel.
There are several other marks put on by the assembler, the barrel staightener, and inspectors.
There is a series on vertical numbers on the underside of the tang that are manufacuring code. This tells information about what machine,operator,shift lot of raw materials and other pertinent info to track quality control. This code was implemented about 2008 when Savage went to the new Okuma maching centers.
The serial # is the last thing to be engraved on the gun, as a matter of fact is is the last operation period. It is done fully assembled right before packing.

http://www.savageshooters.com/archive/index.php/t-11819.html

__________________________________________________

If this is accurate it would appear that the same person proofed all those rifles..Quite possible for a long time employee..

Love them Pre-64's!!!!-Bob

https://membership.nrahq.org/
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sandwarrior
Advanced Member

USA
5533 Posts

Posted - 02/12/2018 :  12:22:56 PM  Show Profile
One thing to look for is a contact ring (brighter brass) at the shoulder/neck junction. Ackley's are supposed to have a .004" interference fit. That ring will tell you if you are actually getting it. Along with a slight increase in pressure to fully close the action.



Every shot serves a purpose, whether accurate or inaccurate. It will always tell you what you did, and did not do, right. Even if all you have is a fraction of a second to make it, learn from it. So the next one is even better.
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wolfpack
Junior Member

494 Posts

Posted - 02/12/2018 :  2:53:58 PM  Show Profile
Thanks Sand warrior. In my research I had read that. I took a black birchwood casey touch up pen ( didn't have an old candle to smoke it) and painted the shoulder/neck section. Not any extra effort to close action but there was a definite mark, a ring, on on the shoulder/neck area. I believe everything Is Ok, but I have a 3 month old grandson that may use it one day, so I think I will have it checked out for the peace of mind.
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rufe-snow
Advanced Member

17865 Posts

Posted - 02/12/2018 :  3:35:46 PM  Show Profile
quote:
Originally posted by wolfpack

Thanks Sand warrior. In my research I had read that. I took a black birchwood casey touch up pen ( didn't have an old candle to smoke it) and painted the shoulder/neck section. Not any extra effort to close action but there was a definite mark, a ring, on on the shoulder/neck area. I believe everything Is Ok, but I have a 3 month old grandson that may use it one day, so I think I will have it checked out for the peace of mind.




Likely all the gunsmith will do, would be to test fire it. As it's a "improved cartridge". No SAMMI spec, go/no go gauges, are going to work.

IMHO you can save yourself some money. By tying it to a old tire with bungie's, and firing with standard 250-3000 ammo. Using 20' of string, tied to the trigger.

Save the fired brass. If you intend to reload. Your going to have to send it to RCBS. To have custom dies made, using the fired brass, to make the correct dimension dies.

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