123 Amax accuracy issues

[LRRPF52]

You may be right. I've been reading about the AMAX and it appears to have a tangent ogive similar to a Berger VLD and I know from experience that those can be very intolerant to bullet jump. I'm going to load some of the 123 AMAX at 2.290" OAL with 28.5 gr 8208. I'm hopeful that a secant ogive bullet like the 120 SMK or PT will provide better results. Honestly, this is a hunting setup, so if I can obtain good accuracy with the ballistic tips I'll be happy.

I think you meant to say secant ogive. I've never had problems getting 123gr A-MAX to shoot well in the Grendel. It has always shot very well for me and many others here. I honestly spend more time shooting steel at distance than chasing groups once I see a good load. Touching the lands at 2.230"?

With the SAAMI chamber, you're partially into the lands almost from the start, since the throat is compound. The real .264 LBC-AR chamber works very well with 123gr A-MAX loaded to 2.245-2.260" COL. There's more than one chamber out there advertised as .264 LBC, that are not the .264 LBC-AR that Les Baer spec'd out.

There's a reason why I prefer Manson reamers for most chamberings. I've had and have seen issues with .308 and .223 Wylde lately as well, where the throats are either too short, or way too long in other calibers.

[molar]

I think you meant to say secant ogive. I've never had problems getting 123gr A-MAX to shoot well in the Grendel. It has always shot very well for me and many others here. I honestly spend more time shooting steel at distance than chasing groups once I see a good load. Touching the lands at 2.230"?

With the SAAMI chamber, you're partially into the lands almost from the start, since the throat is compound. The real .264 LBC-AR chamber works very well with 123gr A-MAX loaded to 2.245-2.260" COL. There's more than one chamber out there advertised as .264 LBC, that are not the .264 LBC-AR that Les Baer spec'd out.

There's a reason why I prefer Manson reamers for most chamberings. I've had and have seen issues with .308 and .223 Wylde lately as well, where the throats are either too short, or way too long in other calibers.

How does the 123 Nosler CC do in the Grendel?

I have an Abolt in 300 Win mag. The detachable mag will allow a max oal of 3.270" and there is a huge jump to the lands as a result. The AMAX and SST's wont shoot at all, yet the 175 gr Nosler is a tack driver. This may be entirely an OAL issue with the 123 AMAX

[bwaites]

So that was your group then? Was that with 28.5 8208? Also, what OAL? Thanks

2.26, in a SAAMI chambered cut rifled barrel. And 28.5 or 28.3, I shot both that day with similar results, I've shot plenty of similar since.

[lwminton]

I think you meant to say secant ogive. I've never had problems getting 123gr A-MAX to shoot well in the Grendel. It has always shot very well for me and many others here. I honestly spend more time shooting steel at distance than chasing groups once I see a good load. Touching the lands at 2.230"?

With the SAAMI chamber, you're partially into the lands almost from the start, since the throat is compound. The real .264 LBC-AR chamber works very well with 123gr A-MAX loaded to 2.245-2.260" COL. There's more than one chamber out there advertised as .264 LBC, that are not the .264 LBC-AR that Les Baer spec'd out.


There's a reason why I prefer Manson reamers for most chamberings. I've had and have seen issues with .308 and .223 Wylde lately as well, where the throats are either too short, or way too long in other calibers.

http://www.hornady.com/store/A-MAX

all the specs and secant it is ...

[SG4247]

Inside dimension of neck is .259" after resizing. Further, I can press hard on a loaded round against my reloading bench and the OAL remains unchanged. Same thing after chambering and then measuring.

.259" is too tight!

Try .261" where all necks fit a pin gauge of that diameter the exact same way.

I have run them at .262" with good results also.

[bwaites]

.259" is too tight!

Try .261" where all necks fit a pin gauge of that diameter the exact same way.

I have run them at .262" with good results also.

SG has it, .002-003 is probably optimal neck tension for accuracy. Its what we try for.

[molar]

SG has it, .002-003 is probably optimal neck tension for accuracy. Its what we try for.

I rechecked some and they come out anywhere between .259 and .260. I guess my options are to either remove material from the expander, which I wouldn't begin to know how to do or buy a bushing type sizer die.

That still doesn't account for why groups with Hornady factory 123 SST's were lousy. I mentioned earlier that I was shooting factory AMAX, but it was actually SST's. I bought a box of 123 AMAX locally to see how they do. Is there usually a large degree of difference in accuracy between the SST and AMAX?

[SG4247]

I rechecked some and they come out anywhere between .259 and .260. I guess my options are to either remove material from the expander, which I wouldn't begin to know how to do or buy a bushing type sizer die.

That still doesn't account for why groups with Hornady factory 123 SST's were lousy. I mentioned earlier that I was shooting factory AMAX, but it was actually SST's. I bought a box of 123 AMAX locally to see how they do. Is there usually a large degree of difference in accuracy between the SST and AMAX?

The Hornady factory ammo Amax/SST will shoot differently (in the same barrel) in my experience.

SST's have a cannular and a crimp I believe. Amax ammo is not made this way.

1/2" to 1-1/2" 5 shot groups at 100 yards from good barrels - with some barrels preferring Amax - and others prefer the SST's.

I even had some lots of same Hornady Grendel ammo that shot wonderful, then the very next lot/box shot not so well....

[SG4247]

Here is the info on neck sizing/expanding:

http://www.accurateshooter.com/technical-articles/reloading/expander-mandrels-and-neck-tension/

I use a 21st century shooter expander set up, since it also works with their neck turning lathe they sell.

SG4247

[molar]

I went to the range today and tested a lot of loads using the 100 and 120 Nosler BT's, 107 and 120 SMK's, and 123 AMAX. I could not get the AMAX to shoot well at all, despite trying several different OAL's up to 2.290". The best load with the AMAX was actually the factory load, which printed 1.5"

I found a couple of good loads with the 120 SMK and 100 BT, both around 0.5 MOA. I really was hoping the 120 BT would shoot accurately, but 1.5" was the best any load did with it.

I supposed the 100 gr BT would make a decent hunting bullet, but what about the 120 SMK? How do the lighter Barnes TSX's do in the Grendel? I may try those next.

120 SMK with 31.0 gr CFE 223

[IMG]CAM00518 by Adam C, on Flickr[/IMG]

100 gr Nosler BT 28.5 gr H335

[IMG]CAM00525 by Adam C, on Flickr[/IMG]

Factory 123 AMAX

[IMG]CAM00514 by Adam C, on Flickr[/IMG]

[LR1955]

I went to the range today and tested a lot of loads using the 100 and 120 Nosler BT's, 107 and 120 SMK's, and 123 AMAX. I could not get the AMAX to shoot well at all, despite trying several different OAL's up to 2.290". The best load with the AMAX was actually the factory load, which printed 1.5"

I found a couple of good loads with the 120 SMK and 100 BT, both around 0.5 MOA. I really was hoping the 120 BT would shoot accurately, but 1.5" was the best any load did with it.

I supposed the 100 gr BT would make a decent hunting bullet, but what about the 120 SMK? How do the lighter Barnes TSX's do in the Grendel? I may try those next.

120 SMK with 31.0 gr CFE 223

[IMG]CAM00518 by Adam C, on Flickr[/IMG]

100 gr Nosler BT 28.5 gr H335

[IMG]CAM00525 by Adam C, on Flickr[/IMG]

Factory 123 AMAX

[IMG]CAM00514 by Adam C, on Flickr[/IMG]

molar:

120 SMK comes through once again.

I recall several years ago a number of guys hunted with the 120 SMK. Killed just as dead just as fast as anything else from what I can remember.

Since then a bunch of 6.5 hunting bullets have come about in the 120 grain range that would fit a Grendel in terms of overall length and I haven't heard of anyone hunting with a 120 SMK since then.

LR55

[molar]

The 120 SMK did pretty well with 8208 as well. Groups with 27.5 and 28 were 0.9 MOA or so. CFE was more finicky. With light charges, I was getting 2 MOA. The higher I went, the more the groups tightened.

I may get some TAC, AR comp, or Leverevolution to play around with the 120 SMK and also to see if I can't get the 120 ballistic tip to shoot. Nosler lists Tac as being the most accurate with the 120 BT.

I also want to try the 100 TTSX and H335. I'm getting some phenomenal groups out of the 70 TSX in a 223 Wylde barrel

[SG4247]

That looks pretty good!

I have a new 16" Shilen hunting rig and shot the 100 gr Nosler and CFE yesterday, with surprisingly poor results (1-2 MOA). Maybe I need some H335?

I was also thinking about loading the Barnes in TTSX in 100 and 120 weights. No TAC in stock here tho.

Never even considered using Sierra for hunting.

Please post your results with Barnes if you try that.

[molar]

That looks pretty good!

I have a new 16" Shilen hunting rig and shot the 100 gr Nosler and CFE yesterday, with surprisingly poor results (1-2 MOA). Maybe I need some H335?

I was also thinking about loading the Barnes in TTSX in 100 and 120 weights. No TAC in stock here tho.

Never even considered using Sierra for hunting.

Please post your results with Barnes if you try that.

I would definitely try some H335. At 29.5 gr H335, which is 1/2 gr over book max, it still held 1 MOA. The first 4 were in one ragged hole with the 5th shot opening it up a little.

CFE is probably a little slow with the 100 gr bullets. That is why I didn't try that combo. The accuracy load according to the Nosler manual for the 100 gr BT is with XBR 8208. It did okay, with a couple of sub moa groups, but nothing like the H335.

[VASCAR2]

There have been several forum members who have gotten good groups using H-335 and my rifle likes 29.0 grains with the 100 grain Nosler BT. I use 29.0 grains H-335 with Barnes 100 grain TTSX and Sierra 100 grain Varmint bullets. I'm not the best shot in the world and this might be hard to believe but all three bullets give me basically the same accuracy at 100 yards. My groups are generally right at an inch or less at one hundred yards unless the shooter messes up.

I've been going to try IMR8208XBR with 100 grain bullets like the A-Max or maybe the 107 grain SMK but I still have several other 100 grain loads to shoot up. The only bullet to give me poor results out of my 16" Shaw 6.5 Grendel has been the 123 grain SMK. I never got a load to shoot less than 1.5 - 2 inch groups at 100 yards. The only other poor performers were the 110 grain PPU FMJ BT and Wolf 100 grain FMJ which give 2-2 1/2 inch groups.