Bullet jump and modern cartridge design

[St. Michael's Armory]

This is my first post on this forum. My question is: is bullet jump as critical or have as much incremental advantage with modern cartridge and chamber designs such as the Creedmoors and PRCs as it does with older cartridges such as the .308 and .300 Win Mag? Take for example a comparison between the 300 WM and 300 PRC, the cartridge designs are very different and particularly the chamber design and dimensions are much tighter in the PRC than the WM. So I could see how bullet jump would create more improvements with the WM where the chamber specs are much looser than with the 300 PRC where the dimensions are more tight and already designed for a cartridge with long aerodynamic bullets.

The reason why I ask is because from what I can tell, it is generally difficult to find box mags in either 6.5 PRC or 300 PRC with any significant room to load bullets longer than SAAMI max cartridge overall length (except Seekins). So is this really a handicap not being able to load out longer bullets given the magazine limits as it would be a handicap for the older cartridges such as the .308 or .300 Win Mag? Thanks for sharing your thoughts.

 

[Eric32]

PrecisionRifleBlog.com - A DATA-DRIVEN Approach to Precision Rifles, Optics & Gear

A DATA-DRIVEN Approach to Precision Rifles, Optics & Gear

precisionrifleblog.com

Find all the articles on bullet jump.

 

[Supersubes]

No difference between the cartridges you mentioned As far as sensitivity. The throat dimensions on the older cartridges were typically sized for lighter bullets than would typically be fired for long range. Particularly true with the 300wm. In the case of the PRC’s, they were designed for those heavy long range bullets from the start. No nead to seat the bullets out to get near the lands, because they’re already there from the start.

 

[Baron23]

PrecisionRifleBlog.com - A DATA-DRIVEN Approach to Precision Rifles, Optics & Gear

A DATA-DRIVEN Approach to Precision Rifles, Optics & Gear

precisionrifleblog.com

Find all the articles on bullet jump.

I really like that guys stuff too and found his article on jump to be very interesting.

oh, and I was USAF too....but we were still flying biplanes! LOL. But I was USAF. Best people I ever worked with.

 

[Eric32]

Them bi-planes still are awesome.

 

[seanh]

I really like that guys stuff too and found his article on jump to be very interesting.

oh, and I was USAF too....but we were still flying biplanes! LOL. But I was USAF. Best people I ever worked with.

Wasn't it the Army Air corps back then

 

[Baron23]

Wasn't it the Army Air corps back then

Haha.....yep, the old brown shoe Air Force LOL

MY UNCLE, however, really was in the Army Air Corp. Flew B-24’s our of Italy, I believe. Those guys had huge stones and never talked about it.

Want to read a good book? Wild Blue by Stephen Ambrose. About those guys and that pig of an aircraft. Great read and there is a very surprising character in there.

thanks for the memories.

 

[308pirate]

This is my first post on this forum. My question is: is bullet jump as critical or have as much incremental advantage with modern cartridge and chamber designs such as the Creedmoors and PRCs as it does with older cartridges such as the .308 and .300 Win Mag? Take for example a comparison between the 300 WM and 300 PRC, the cartridge designs are very different and particularly the chamber design and dimensions are much tighter in the PRC than the WM. So I could see how bullet jump would create more improvements with the WM where the chamber specs are much looser than with the 300 PRC where the dimensions are more tight and already designed for a cartridge with long aerodynamic bullets.

The reason why I ask is because from what I can tell, it is generally difficult to find box mags in either 6.5 PRC or 300 PRC with any significant room to load bullets longer than SAAMI max cartridge overall length (except Seekins). So is this really a handicap not being able to load out longer bullets given the magazine limits as it would be a handicap for the older cartridges such as the .308 or .300 Win Mag? Thanks for sharing your thoughts.

I think people tend to extrapolate what benchresters do into other rifle disciplines without really testing things.

Bullet Jump Research

www.shortactioncustoms.com

 

[lash]

This is my first post on this forum. My question is: is bullet jump as critical or have as much incremental advantage with modern cartridge and chamber designs such as the Creedmoors and PRCs as it does with older cartridges such as the .308 and .300 Win Mag? Take for example a comparison between the 300 WM and 300 PRC, the cartridge designs are very different and particularly the chamber design and dimensions are much tighter in the PRC than the WM. So I could see how bullet jump would create more improvements with the WM where the chamber specs are much looser than with the 300 PRC where the dimensions are more tight and already designed for a cartridge with long aerodynamic bullets.

The reason why I ask is because from what I can tell, it is generally difficult to find box mags in either 6.5 PRC or 300 PRC with any significant room to load bullets longer than SAAMI max cartridge overall length (except Seekins). So is this really a handicap not being able to load out longer bullets given the magazine limits as it would be a handicap for the older cartridges such as the .308 or .300 Win Mag? Thanks for sharing your thoughts.

It’s not as much about cartridge design as it is bullet design. All of those cartridges can be made to shoot just fine if you use a bullet that is designed for jump insensitivity.

I shoot a .260 Remington, which is very much the old style cartridge design, with a 40* included shoulder and no room for seating them long in a mag. But I shoot a 136g Lapua Scenar L that is a very forgiving bullet design. With a new barrel, I usually start at about 0.015-0.020” out and never touch it through the life of the barrel.