80 grain VLD loads for AR15

[kiwibanger]

Like yesplease, I am also looking for some advice. Also running a Rock River, 20" Wilson barrel, 1:8 twist, Wylde chamber. It is very accurate with most loads. I'm experimenting with Targex 80grain VLDs. Loading to 2.53", just touching the rifling. All fine, but these definitely will not fit in a magazine.
Does anyone out there have any experience of loading these super long bullets to an OAL which will magazine feed? I know I can load the Sierra 77 to mag feed, but I'm working with the 80 VLD due its potential at extreme ranges. Only if it's safe. Will be using BM2, AR2208, and VN135.
Any advice most appreciated

[Herbmiester]

I cant comment on the Targex bullet but if it is similar in profile to the Sierra 80 you will likely not get it seated without the ogive being inside the case mouth at magazine length. The 77gn Sierra was designed to allow it to be seated with the ogive above the case mouth. The 77 gn bullet has the bearing surface bought forward and a less ballistically efficient ogive so it will work in a magazine. The 77 is a compromise but a pretty good one. Some times they are known as Length Tolerant Bullets as oppossed to VLD bullets.

To sum up 80gn bullets that are not LTB have a better BC but cant practically be loaded to AR magazine lenth. However you can try cutting away the front of your AR magazine. A slot just wide enough to allow the bullet tips to sit out may give you the few mm needed to get your ogive above the case mouth. I have seen this done before, the magazines become a bit fragile and they can deform just from the pressure of the loaded rounds.

The 80gn bullets do work but the last time I did the calculations they were only coming into thier own at 600 yards plus, so I guess its about what you want to achieve. I like the 70gn Berger as you can still drive it 2900 FPS with the right barrel chamber combo. BC is important but so is muzzle velocity.

[colt45]

The only 80gr projies I have ever managed to get to seat properly and feed reliably in an AR are Hornady 80gr FMJ.
I tried with 75gr Hornady amax's, but ran into the same issues that Herbmiester has described, projy seated below the ogive into the case, not a good idea, as pressures can start to get excessive and you cant get anywhere enough powder into the case to drive them fast enough to benefit from the projectiles design and weight.
Perhaps the best option is what I did with a 6mm PPC Sako varmint rifle I had a few years ago,(damn I wish I had never sold it ), fitted an insert into the mag that basically stopped the mag spring from compressing and a channel machined into the top surface that you sat the round into then single fed it.
I am sure you can get the same thing for an AR, lets the rifle still function fine, fires, cycles and locks back for the next round to be put in place, I am sure that Sinclair Intl sell them, called a "mag sled" or something like that, can't remember now.

Have you tries Bryn's (Targex) 69gr Rebated Boat Tail HP's?
I swap around between Sierra's 77gr'ers and Bryns 69gr'ers and don't even need to change scope settings till you start getting past 350y'ds, and they are pretty devastating on bunnies.
What sort of ranges are you looking for?
Saw some footage a while ago of a guy consistently hitting 12" x 24" plate at 800yds with a std Bushmaster varmint AR, impressive and inspiring.

Cheers

[colt45]

[quote="Herbmiester"] The 77gn Sierra was designed to allow it to be seated with the ogive above the case mouth. The 77 gn bullet has the bearing surface bought forward and a less ballistically efficient ogive so it will work in a magazine./quote]

I heard a story that the Sierra 77gr was actually designed to be run in an AR and was loaded by Lake City as a factory round for use by Spec Ops in short barreled carbines to make up for velocity loss by increasing energy into target.
Dunno how true it is but makes for an interesting read.

[Herbmiester]

My understanding of the 77 sierra was that it was designed from the outset to work in the Magazine of an AR15. As to the military aspect, try putting "Mk 262" into Google and you will find a lot of info on the Military application of the 77gn projectile. The original load didn't have a cannalure the Mod 1 round did and Nosler also supplied some projectiles. The MK 262 mod 1 is not general issue ammunition.

[Monsterbishi]

My understanding of the 77 sierra was that it was designed from the outset to work in the Magazine of an AR15. As to the military aspect, try putting "Mk 262" into Google and you will find a lot of info on the Military application of the 77gn projectile. The original load didn't have a cannalure the Mod 1 round did and Nosler also supplied some projectiles. The MK 262 mod 1 is not general issue ammunition.

The twist to mk262 being normal length is that the proper black hills stuff uses a blend of powder with unobtainium in it to achieve the listed muzzle velocities without crazy pressure issues.

Us normal folk just have to bend over and kiss a coupla hundred fps goodbye

[Herbmiester]

Black Hills makes 2 loads one for 223 pressure levels and one for 5.56 levels. If you have a 5.56 chamber 2800fps from a 20 inch barrel is realistic, a 223 Wylde may get you there as well.

[kiwibanger]

Thanks all for your comments. Saved me a lot of trial and error. I'll reserve the 80VLDs for single loading, extreme long range shots. And I'll be trying out those Sierra 77s.