Long Range Hunting Online Magazine

Go Back   Long Range Hunting Online Magazine > Chatting and General Stuff > General Discussion

General Discussion Must wear red or OD green socks to participate. I can't see your socks, please be honest.


Factory ammo in custom chambers

LinkBack Thread Tools Display Modes
Unread 10-07-2011, 09:15 AM
Platinum Member
Join Date: Jul 2004
Location: Texas
Posts: 7,193
Factory ammo in custom chambers

Over the years I have seen factory ammo that was loaded to hot for "Custom" chambers and
have experienced this again with the new Superformance ammo.

Note;This is not a criticism of the ammo just a warning if it is used in anything but a SAMMI

With out a doubt, it does prodeuce more velocity. But in all of the SAMMI chambered rifles it
was tested in it is "MAX" Pressure and the signs were present (Heavy bolt lift,ejector marks on
the case head and flat primers.

I have not tested it in a factory chambered rifle so any input would be appreciated to put
everything into perspective.

Most on this site load there own ammo and start low and work up, But some use factory ammo
to form a basis for accuracy and velocity, and use it to do break in on new barrels. My concern
is that someone will use the HOT factory ammo on there short throat ed,Tight necked minimum
free bore chambered rifle and have problems.

This is not the first ammo that has not been suitable for custom chambers, My first experance with
this probablem was the big Weatherby cartriges that were loaded to the Max for there factory rifles
with tons of free bore. If this ammo was fired in a custom chamber with tighter dimensions and
little or no free bore it would blow the primers and cause heavy bolt lift.

So if you have a custom chamber and want to get more velocity some factory loaded ammo may
cause problems and could even be dangerous.

As stated earlier, This ammo has performed well and with the longer peak pressure curve has
all the things we want in order to achieve max velocity, but there is no free ride and make no
mistake about it these are MAXIMUM pressures and come with the problems associated with
Maximum loads.

MY recommendations for what it's worth, is not to shoot any of the high pressure ammo in a custom
chamber unless it is SAMMI spec.

Comments are more than welcome. It may keep someone from having a problem or even getting

Just a heads up

Reply With Quote

Unread 10-07-2011, 11:09 AM
Silver Member
Join Date: Jul 2010
Posts: 420
Re: Factory ammo in custom chambers

I will mirror JE customs concern about factory ammunition in custom chambers. The 338-378 is a prime example. The original person who had the rifle built is always repeatedly informed that his short throat is no longer a 338-378 Weatherby. The thing that chokes my goat is the amount of custom chamberings that the barrels are engraved as being the original parent cartridge.
Reply With Quote
Unread 10-08-2011, 08:00 AM
Join Date: Mar 2010
Location: on the Southern Plains
Posts: 1,971
Re: Factory ammo in custom chambers

Chambers that are not SAAMI need to have the dimentions that are altered on the barrel, engraved or , at least, stamped.
"Shoots real good!": definition; it didn't blow-up in my face. 1993 graduate Montgomery Community College 2yr. gunsmithing program
Reply With Quote
Unread 10-12-2011, 04:38 PM
Platinum Member
Join Date: Jul 2004
Location: Texas
Posts: 7,193
Re: Factory ammo in custom chambers

Originally Posted by shortgrass View Post
Chambers that are not SAAMI need to have the dimentions that are altered on the barrel, engraved or , at least, stamped.


I have encountered rifles that had been altered even to the point of rechambering to a larger
case/cartrige that had not been changed.

It is the obligation and responsibility of everyone that alters a chamber to give a good description
of the cartrige and special dimensions.

Also I have an update on more of the Superformance ammo. It appears that when fired in an AI
chamber that it is not as hot as a standard chamber. (When SAMMI loaded ammo is used while
fireforming) The extra chamber space allows the case to expand lowering the pressure.

Both chambers had the same free bore and neck size but one had been Improved.

Anyone else that uses this ammo please look at the brass and add your comments.

Reply With Quote


Thread Tools
Display Modes

Similar Threads for: Factory ammo in custom chambers
Thread Thread Starter Forum Replies Last Post
?Caliber of custom, long rang hunting rifle: low recoil using brake and factory ammo? mjm0073 Long Range Hunting & Shooting 11 01-14-2014 02:47 AM
Nosler Custom Ammo fitting 280AI chambers? dporter99 Rifles, Bullets, Barrels & Ballistics 14 09-01-2010 08:38 PM
Custom Rifle, Factory Ammo bebberson Rifles, Bullets, Barrels & Ballistics 1 01-26-2009 12:09 PM
custom chambers and sizing dies American_pride Rifles, Bullets, Barrels & Ballistics 3 05-05-2008 03:52 PM
Custom barrels and factory ammo winmagman Rifles, Bullets, Barrels & Ballistics 4 12-21-2007 06:44 PM

All times are GMT -5. The time now is 05:40 AM.

All content ©2010-2015 Long Range Hunting, LLC