Maximum case neck length?

[SteveOak]

At what point does case neck length become a problem?

I have a 6mmBR and am looking at loading some quite heavy bullets, 120 to 125gr for the 500 meter targets. They would protrude quite far into the case, significantly affecting case capacity.

I also would continue loading 105 to 108gr class bullets for the shorter distances, 200 to 385 meters. Presently using the Sierra 107gr MK.

Making a case with a longer neck would allow me to seat the bullets further out, preserving somewhat the case capacity.

Fortunately I only need to get 2,650 or so fps with the heavy bullets. VV N550 should help with that.

I will try them with the case I have first. Just wondering what the limitation on neck length would be.

The neck now is the standard 0.322". I would have to make cases from something a bit longer, maybe a 6XC.

 

[Ggmac]

I'm confused , you want a longer neck to seat heavier bullets and not take up case cap ? So just seat your bullets out further , the existing case neck will hold your bullets fine . Or am I missing something, it's not April 1 is it ?
No , I just double checked .

 

[Shawnba67]

There is a fellow that chambers 6xc with a neck long enough to use formed 308 brass with little or no trimming. Thats over .400 neck. I almost did mine that way. I have also heard several say you only need 0.060 in the neck to hold a bullet for target type use. Hit ebay and snag a .275 chucking reamer and go for it!

 

[tmwinds]

I assume you are talking about switching barrels for the two different bullets. If not I'm afraid you will end up with a barrel that will not shoot either the 105 or 126 gr. bullets very well. They will require a different twist rate and free bore.

Also, I can't think of a better round for 200-500 yards than your reliable old 6BR 8 twist barrel and 80-108 gr. bullets.

 

[Ringostar]

With the distances that he mentioned. It sounds like he's talking about silhouette competition. If so, the lighter 6mm bullets don't always have enough energy at 500m to knock over the heavy ram targets.

 

[tmwinds]

With the distances that he mentioned. It sounds like he's talking about silhouette competition. If so, the lighter 6mm bullets don't always have enough energy at 500m to knock over the heavy ram targets.

If that is the case I agree that the 105's in a 6br would be marginal on the 500m rams. I still don't think that trying to shoot 105 gr. bullets and 126 gr. bullets from the same 6BR barrel will work. I shot pistol and rifle silhouette many years ago. For pistol I shot 7mm IHMSA and for rifle a .308 or 7-08 was hard to beat. There are probably better rounds available today. The 6.5.'s would seem like a good solution.

 

[SteveOak]

I am shooting Silhouette and presently using Sierra 107's for 200, 300 and 385 meters. For my money the 6BR/Sierra 107 MK is the perfect cartridge/bullet combination for those three targets.

The 500 meter target is a completely different animal (sorry, couldn't help it ). I have tried a bunch of different bullets and am having good success with DTAC 115s using 29.2gr N150 and getting 2,708 FPS.

Some of the shooters here are using Berger 115 Target and Hunting bullets and I wanted to try them. With Varget and the Berger 115's I seemed to run into case capacity limitations so I tried the DTACs and ended up switching to N150 anyway because the recoil impulse was less sharp. With N150 I think I can get the same velocity with the 115 Bergers.

I have found a source for heavier bullets, 120, 121 and 125gr that I would like to try. I might be able to get usable velocity with N550 but if I am near the limit I might have temperature sensitivity driven problems in the summer in Phoenix.

Ggmac, there are literally thousands of posts on here discussing seating the bullet to the lands and adjusting for accuracy. Here is a link for you. http://bfy.tw/IUTd

 

[Ggmac]

I am shooting Silhouette and presently using Sierra 107's for 200, 300 and 385 meters. For my money the 6BR/Sierra 107 MK is the perfect cartridge/bullet combination for those three targets.

The 500 meter target is a completely different animal (sorry, couldn't help it ). I have tried a bunch of different bullets and am having good success with DTAC 115s using 29.2gr N150 and getting 2,708 FPS.

Some of the shooters here are using Berger 115 Target and Hunting bullets and I wanted to try them. With Varget and the Berger 115's I seemed to run into case capacity limitations so I tried the DTACs and ended up switching to N150 anyway because the recoil impulse was less sharp. With N150 I think I can get the same velocity with the 115 Bergers.

I have found a source for heavier bullets, 120, 121 and 125gr that I would like to try. I might be able to get usable velocity with N550 but if I am near the limit I might have temperature sensitivity driven problems in the summer in Phoenix.

Ggmac, there are literally thousands of posts on here discussing seating the bullet to the lands and adjusting for accuracy. Here is a link for you. http://bfy.tw/IUTd

I've had necks .75" long during my experimenting days and found them totally useless . Stick with a conventional case and adjust your ball seat/ freebore . Don't listen to newbie wannabe smiths . I can send you an email showing my variation of 6 br with various neck lengths . Some were formed with 30-06 brass , 8 mm , and 308 . If you want to talk about chambering issues , try a 6 br with a 3/4" neck .
I understand what you want but the why is what's I'm puzzled about . Neck length is sufficient for seating the heavy bullets out ,so case capacity isn't diminished.

 

[Ggmac]

I am shooting Silhouette and presently using Sierra 107's for 200, 300 and 385 meters. For my money the 6BR/Sierra 107 MK is the perfect cartridge/bullet combination for those three targets.

The 500 meter target is a completely different animal (sorry, couldn't help it ). I have tried a bunch of different bullets and am having good success with DTAC 115s using 29.2gr N150 and getting 2,708 FPS.

Some of the shooters here are using Berger 115 Target and Hunting bullets and I wanted to try them. With Varget and the Berger 115's I seemed to run into case capacity limitations so I tried the DTACs and ended up switching to N150 anyway because the recoil impulse was less sharp. With N150 I think I can get the same velocity with the 115 Bergers.

I have found a source for heavier bullets, 120, 121 and 125gr that I would like to try. I might be able to get usable velocity with N550 but if I am near the limit I might have temperature sensitivity driven problems in the summer in Phoenix.

Ggmac, there are literally thousands of posts on here discussing seating the bullet to the lands and adjusting for accuracy. Here is a link for you. http://bfy.tw/IUTd

If you decide to go that route , I have the form dies to make necks as long as you need . 3 or 4 die set . Was necessary when I was ' playing ' with case design .