Good load for 7.62x51 with 1/10 twist?

[JohnC]

So I'm toying around with some reloading and I wanted to work up some accurate long range ammo for my Sig 716.

http://www.sigsauer.com/CatalogProductDetails/sig716-patrol.aspx

Specs are 16 inch barrel with 1/10 twist. Nothing special, but it's proven to be quite consistent and accurate with regular Federal Lake City M80. That's what sparked my interest in seeing how accurate this rifle can be with some hand loads.

At the moment, I don't have have 175 grain bullets.

What I do have are some 168 grain HPBT's along with IMR 4895, IMR 4166, and IMR 8208 XBR. I'm using CCI #200 primers and once fired Federal Lake City 7.62X51 brass.

So what's working good in your AR10's with 1/10 twist 16in barrel? Shoot me some reloading data! :D

Edited January 5, 2016 by JohnC

[atlas3025]

I have had good success in my SCAR with 168SMK's and Varget (the load that is on the bottle), but I haven't tried any of the powders you have listed there.

[mike_f]

I haven't loaded for a 308 AR, but for M1A/M14 type rifles IMR 4895 was a common powder used in highpower matches.

 

Typical top loads were 42gr for military brass / 43gr for commercial brass with a Sierra 168 gr BTHP, OAL 2.800".

 

As always, start low and work up to those loads to see what works in your rifle.

[JohnC]

I might pick up some more 168 and 175 grain bullets today. 

Edited January 6, 2016 by JohnC

[atlas3025]

Well, the SMK is an HPBT.  But I am sure there are other HPBT's out there.  SMK's are definitely match proven.

 

From what I understand, the 175 is a better choice for 1000 yard because in most guns, the bullet will still be supersonic at that distance whereas the 168's may be transonic.

[JohnC]

I should have known that... Need a cup of coffee to kick-start the brain this AM. :lol:

 

I'll go for some 175's then! Thanks! 

Edited January 6, 2016 by JohnC

[Caster]

FC case
Winchester large rifle primer
44.0g of IMR 4166
150g Sierra Game King


This will make a 2.00 inch group at 100 yards from my FNAR......and that's a TEN round group. Not some cheaters 3 round group that only tell lies. This is my 'Go To' inventoried load. It's about the ONLY .308 load I currently load. I shoot this load stone cold barrel or so hot I get heat mirage in the scope, it performs the same every time.
From a fouled, warm (not hot) barrel, it will put 5 rounds in a 1 inch circle at 100 but opens up a touch as heat builds. Some of it may have to do with the fact that I am a sucky shooter too.
I'm loving the new Enduron powder too by the way.


As always, start with a starting load and consult your load manual. Use at your own risk. Edited January 6, 2016 by Caster

[JohnC]

So far...

 

I loaded 20 rounds with:

HPBT 168 gr bullets

IMR 4895 with 43.5 gr

CCI #200 Primers

 

And 19 (lost one nickle case at the range)

HPBT 168 gr bullets

IMR 4208 with 42.5 gr

CCI #200 Primers

 

Working on another 40rds....  

[mike_f]

 

So far...

 

I loaded 20 rounds with:

HPBT 168 gr bullets

IMR 4895 with 43.5 gr

CCI #200 Primers

 

(snip)

 

The max load for that bullet weight in the online IMR Loading Data is 44 gr, with a starting load of 41 gr.

 

If you haven't already worked up to the 43.5 grains of IMR 4895 with those components in that rifle, I advise against starting there.

 

If you already worked up to your current powder charge, then never mind. :)

[JohnC]

I figured I was starting a bit median range since the IMR Basic Reloading Manual I got at the NRA Convention had the Max Load at 45.4C.






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Edited January 6, 2016 by JohnC

[JohnC]

Fwiw, couldn't find any 175's so I went with 178 grain A-Max.




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Edited January 6, 2016 by JohnC

[atlas3025]

It should be close.  I wouldn't be surprised if pressure is the same because of that ogive that the AMAX has.  

[mike_f]

I figured I was starting a bit median range since the IMR Basic Reloading Manual I got at the NRA Convention had the Max Load at 45.4C.


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You're right, I was looking at the load for the Barnes bullet that lists the max @ 44gr.

 

You mentioned Lake City brass and nickel plated brass in your previous posts.  If you're using either one of those, it is customary to reduce the published charges by 1 grain.  Military brass tends to be thicker and the nickel plating adds thickness. If the rule of thumb of reducing the charge by 1 gr is applied, then max load would be 44.4 grains with your initial load being 43.5 gr.

 

Personally, I still wouldn't start there (assuming this is the first time loading with these components for this rifle), but it's up to you. :) (my intention is to be helpful and not scolding, but it's hard to convey that online)

[JohnC]

You're right, I was looking at the load for the Barnes bullet that lists the max @ 44gr.
 
You mentioned Lake City brass and nickel plated brass in your previous posts.  If you're using either one of those, it is customary to reduce the published charges by 1 grain.  Military brass tends to be thicker and the nickel plating adds thickness. If the rule of thumb of reducing the charge by 1 gr is applied, then max load would be 44.4 grains with your initial load being 43.5 gr.
 
Personally, I still wouldn't start there (assuming this is the first time loading with these components for this rifle), but it's up to you. :) (my intention is to be helpful and not scolding, but it's hard to convey that online)

The help is much appreciated. You don't need to filter anything for me. I take constructive criticism well. :up:

It's been so long since I've reloaded, I've forgotten too much. Plus, I never used to own military brass, etc. I mostly loaded .270 Winchester and pistol ammo. So this 7.62x51 AR10 stuff is new to me.

[JohnC]

This is the brass I'm using...








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[mike_f]

The help is much appreciated. You don't need to filter anything for me. I take constructive criticism well. :up:

It's been so long since I've reloaded, I've forgotten too much. Plus, I never used to own military brass, etc. I mostly loaded .270 Winchester and pistol ammo. So this 7.62x51 AR10 stuff is new to me.

 

 

I'm happy to share my $0.02, FWIW.  Also, there's nothing original or magical about the way I do it.  It's is heavily influenced by the fact that I've had to disassemble at least my share of reloaded rounds. 

 

 

This is the brass I'm using...

(snip)

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I reduce loads in anything 30 caliber with the "LC" headstamp by 1 grain.  The LC 5.56 brass that I've loaded doesn't seem to have the volume difference vs. commercial brass, so I don't do the 1 grain difference on that (YMMV).  I also reduce load by 1 gr for nickel plated brass.

[Hozzie]

This is a perfect example where Quickloads can help you. You can check different bullets and different powders without loading anything first. It will at least let you know if a load is most likely safe.

Based on base data for 308, the 43.5gr of IMR 4895 with 168gr bullet at 2.80 OAL is about 52,000 psi. Well below the 62,000 psi max. If OAL is smaller, pressures will go up of course. Knowing the case capacity in H2O is also important as this can change things quite a bit. Edited January 7, 2016 by Hozzie

[mike_f]

Not to enable to your reloading habit any further, but if you're going to reload in quantity, check into Shooter's Pro Shop for over run/blem Nosler bullets.

 

They frequently run good sales (on bullets and loaded ammo) and have a military/first responder discount. Shipping is a fixed rate of $12.

 

In stock right now they have .308" 168 gr BTHP Match bullets for $21.95/100. 

 

http://www.shootersproshop.com/nosler-products/nosler-blemished-2nds/nosler-blemished-bullets/nosler-30-168gr-custom-competition-hpbt-blem-100ct.html

 

I've found the Nosler match bullets to generally be as accurate as Sierra or Hornady match bullets (but I'm not a great shooter or shooting in accuracy matches).  I buy either 155 gr, 168 gr, or 175 gr match bullets solely based on price.  I'm not shooting past 600 yards, so there's not a significant difference for me.

[JohnC]

Blehh, my A-Max load isn't working out I don't think.

None of my manuals have a load for this bullet, so I went with a 175 gr load and went way lower than max powder charge for the 178 gr A-Max, but it wasn't fitting in the mag because of the plastic tip.

So I kept adjusting my Dillon bullet seating die until it cleared the mag (it's still near touching the inside of the mag), but it put a good ring on the bullet.

It makes me think the bullet is too long for this powder charge and the seating die might have put too much pressure on the bullet.

Picture coming...

[JohnC]

Here it is..






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[Hozzie]

Sending you a PM.  I will help you check some things.

[JohnC]

PM sent. Thanks for the help. :up:

[JohnC]

Found this on the Hodgdon site.




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[mikegideon]

Blehh, my A-Max load isn't working out I don't think.

None of my manuals have a load for this bullet, so I went with a 175 gr load and went way lower than max powder charge for the 178 gr A-Max, but it wasn't fitting in the mag because of the plastic tip.

So I kept adjusting my Dillon bullet seating die until it cleared the mag (it's still near touching the inside of the mag), but it put a good ring on the bullet.

It makes me think the bullet is too long for this powder charge and the seating die might have put too much pressure on the bullet.

Picture coming...

 

Here's the problem... as you increase your seating depth, pressure can increase dramatically. You need to be careful! Watch for pressure signs (primer flattening and ejector swipes). I have loaded AMAX in 223. The ones I own cannot be loaded to AR mag length. Hornady should have load data on that bullet.

 

80 grain AMAX and 77 grain Sierra Matchking (mag length). If I loaded the AMAX to mag length, it could kaboom the gun.

 

Edited January 7, 2016 by mikegideon

[JohnC]

Thanks for the info, Mike.

I pulled the bullet and trashed the load earlier.

I then drastically lowered the powder charge after some research.

I used 37 grains of IMR 8208 XBR. The powder is well below the neck. Not a compressed load and did not leave a ring on the bullet like my first try.





Next to a factory M80



Clears PMAG