Need help identifying short ogive 6mm bullets for the 6x45 AR.

[Nightvisionary]

I recently put together a 6x45 AR upper. It has a 20 inch 1/8 twist barrel. After doing much research here and elsewhere to find appropriate bullets weights for my barrel, I read that the ogives on most 6mm bullets are too long to meet the 2.260 COAL needed to fit into AR magazines.

Over the last month I have worked up and fired many loads using Hornady 75 grn HP's, Hornady 87 grn BTHP's, Nosler 95 grain ballistic tips, Sierra 90 FMJ Gamekings, and Barnes 85 grn TSX bullets. All were loaded at 2.265 OAL, slightly over length but still fed reliably.

The Sierra 90's and Hornady 75's gave me mediocre accuracy and the Nosler 95's gave the best.

After reading about the ogive issues last night I tried to look up the dimensions of various 6mm bullets including those I have loaded and couldn't find much at all listed on the manufacturers websites.

With no other ideas I took all of the bullets I mentioned and determined the end of the ogive by placing them tip first into a sized case until I felt resistance then marked a ring around the bullet where it met the case neck. Not the most accurate method Im sure, but it was the only idea I had.

I then seated the bullets normally until the line around the bullet met the case neck. Using this method I determined the ogives on all the bullets with the exception of the Sierra 90 grn were to long to load to magazine length without seating the ogive into the neck.

The problem with the Sierra 90's besides accuracy is I believe they are discontinued. Every vendor I have found online including Sierra lists them as out of stock with no back order available. I just happened to find a single box locally.

I figured I can trim the cases to 1.740 to get a little more room while still keeping acceptable neck tension.

Any suggestions would be greatly appreciated.

 

[357Mag]

Night VIz -

Had trouble posting my first reply.

Give Sierra 6mm 85BTHPs a try. They are the most consistent 6mm bullets by-wt, of all those I've wt-sorted ( includes customs ).

They are hyper accurate ( in my rifle, w/ my loads anywayz ).

IMHO: the 85BTHPs oughta' feed from a magazine in an AR, just fine.

Regards,
357Mag

 

[areaone]

Try the Speer 75 gr HP, or the 75 gr sierra, the 85 gr BTHP Sierra is a super all purpose 6mm bullet, shoots on the same level as my bergers from my 6br. Also have used it on coyote and 2 antelope, one. in excess of 500 yds on an antelope from a 6mm Remington.

 

[Browningguy]

The best I load I found in my 6x45 AR was the 80 gr. Sierra SSP bullet.

 

[Dan877]

I'm also working up loads for my new 6x45 AR-15, but I'm concentrating on lighter bullets, 80grains or less. A couple of things I've learned from researching the whole OAL problem is:

1. Try different mags. C-Products stainless steel magazines are wide enough to be able to load to 2.280 OAL. I bought 2 of them specifically for my 6X45, and I can actually load out to 2.290 OAL but they don't feed reliably. Rather than sticking to a fixed 2.260 length, check your mags and see what OAL they can actually hold.

2. For really long bullets modify a mag by removing the front, as shown on this web page:
http://www272.pair.com/stevewag/armags/armags.html

 

[Nightvisionary]

I sure appreciate all the excellent suggestions. Is there any resource that lists bullet ogive numbers? From what I have gathered the 6x45 is limited to a 7 ogive or lower for magazine length cartridges.

 

[Nightvisionary]

I'm also working up loads for my new 6x45 AR-15, but I'm concentrating on lighter bullets, 80grains or less. A couple of things I've learned from researching the whole OAL problem is:

1. Try different mags. C-Products stainless steel magazines are wide enough to be able to load to 2.280 OAL. I bought 2 of them specifically for my 6X45, and I can actually load out to 2.290 OAL but they don't feed reliably. Rather than sticking to a fixed 2.260 length, check your mags and see what OAL they can actually hold.

2. For really long bullets modify a mag by removing the front, as shown on this web page:
http://www272.pair.com/stevewag/armags/armags.html

Great idea with the magazines. I have measured my Colt 20's, 30's and P-Mags. I have heard before that the C-products mags give a little more room. The magazine modification is a very interesting idea, particularly for hunting and 600 yd matches.