16" Barrel reloads

[hydrotech]

Do you use a sandbag under your stock that you can squeeze to help hold aim point still? I'm new to shooting off a bench. I had just been using my bipod for the from and holding the rear against my shoulder. Then a buddy let me use his sandbag under my stock and it took my 1 inch groups down to cloverleafs.

[Deezil]

Yep. Sandbags. I'm a good shot, so no flyers. I can do .8" groups with factory ammo so I know it's not me. I'll order some 120gr ttsx tomorrow. Definitely ordering a new AA 18" barrel when funds allow I think.

[stokesrj]

It would be quite normal for a gun that shoots .9 MOA with one load to shoot 1.5 MOA with another. The Barns bullets are particularly finicky. But there probably is a node that will perform well at another charge weight or seating depth. It may be outside of mag length or safety constraints.
Bob

[Drifter]

The Barns bullets are particularly finicky. But there probably is a node that will perform well at another charge weight or seating depth.

I agree with Bob regarding the potential finickiness of Barnes bullets. Although I haven't yet attempted to dial in a load with the 6.5 100gr TTSX, I've used TTSX's in another cartridge. In the particular barrel I was loading for, accuracy was much better if starting with a clean barrel and shooting only those bullets. While it might not always apply, I don't think that I'm the only one who has noticed that the TTSX sometimes doesn't shoot well in a barrel fouled with other bullets and powders.

Another potentially helpful tip is to load a batch of test loads to mag length, and take a bullet seating die (preferably one with the micrometer-type adjustment) in a Lee hand press (~$25) to the range (along with something to measure COL). If the long loads don't shoot well after a couple of groups, use the hand press to seat the bullets a little deeper, perhaps ~0.005" at a time. Of course, don't go excessively short, but you might notice a slight difference in group size with each COL. If you normally crimp, you can also take along a crimp die in a hand press, and leave the initial test loads uncrimped, allowing you to perform that task after each individual COL adjustment. (If you don't normally crimp, it might be worth trying it if you really want to explore all options to make a particular bullet shoot to its potential from a particular barrel.) This advice might seem odd, but it beats the heck out of loading a bunch of rounds at the same COL only to realize in just a few shots that they ain't gonna shoot well regardless of charge variations, or loading a bunch of charge variations and COL variations beforehand, and / or making numerous range trips to find the right COL.

[rasp65]

I loaded some up for hunting season. The first time out I loaded 20 and shot 4 groups ave below 1", one group .6". Next time out same load 4 groups ave 1.5" and shot 1 into water filled jugs to collect bullet . While weighing the bullet I compared it to unfired samples. What I found is the weights of the bullets was not consistent at all. I think in the future I will sort them by weight and see if that improves the groups.

[Deezil]

I ordered some 120 gr TTSX, my gun seems to shoot decent 120gr bullet groups, so I guess Ill try it, we will see in another week when the bullets arrive. I use barnes in my 7mm mag, they shoot awesome in that, and Ive read enough reports that others are having good luck. Its probably my barrel, but I figure if I can pull off ok factory ammo groups I should be able to load something at the least on par with them.

[Deezil]

Ill toy with seating depths tonight and hit the range tomorrow hopefully.

[Kikn]

I noticed when I setup my initial loads with TAC I was able to shoot the same hole with a sandbag at 100yds with the A-MAX 123, using the same load with the Barnes TSX 120 (Not TTSX) my groups were somewhat erradic +/- 1.5 moa

[Deezil]

so your thinking its the bullets? My gunstore here has some 120gr noslers.. maybe Ill get them to play with too, I was trying to stay away from lead bullets really, but Id rather have accuracy than anything out of it.

[Deezil]

wondering on the 100gr if I need to load them hotter with my shorter barrel? Maybe they are not fast enough yet? What signs do I look for on these other than the primer?

[rasp65]

Pulling pieces of metal out of your face.

[Deezil]

Pulling pieces of metal out of your face.

not sure if you know anything about realoading, but there is signs to look for before that. I know about looking at primers, but anything else?

[rasp65]

Case head expansion, smears on case head from brass flowing into ejector or extractor cuts, primer pocket expansion, blown primers.

[Drifter]

...there is signs to look for before that. I know about looking at primers, but anything else?

In addition to inspecting fired brass, watch your chronograph as you shoot through your work-up loads. If an incremental step up in charge doesn't show the same approximate fps increase as previous steps, go back to previous lesser charge and consider it max.

Keep potential powder temp sensitivity in mind, factoring in temps during testing and expected temps during later use. A max load in cold weather might be unsafe during hot weather.

I understand the desire to run hunting loads as fast as safely possible, but accuracy is often better at less-than-max charges.

[stokesrj]

The case and primer indications of excessive pressure require some experience to interpret correctly in the AR platform. Even flattened primers need to be interpreted with considerations allowed for the particular primer in use. The primer cup thickness and hardness will hide excessive pressures if you are using primers that are designed for the AR. The reason for this is that small rifle primers like the CCI 400, Remington 6.5, Winchester Small Rifle and similar primers are to easily ignited by firing pin inertia when the bolt slams home on an easily chambered round. I see this every year at the national matches when you have 150 AR's on the line and the command "with one round load" is given. One or more will go boom and the tower will usually respond with something like "you are now ten points behind". I've personally investigated three of these and found in each case it was Winchester Small Rifle Primers.
To prevent this Remington makes a 7.5 primer with a thick cup, so does CCI with the 41 which is specifically made for the AR but also the 450 and BR4 use the same thick walled cup. Wolf makes the SRM and AR primers also with thick cups. These are the ones you should be using in an AR platform however they are also less revealing of pressure problems.
Loads that will easily flatten or even pierce a Remington 6.5 primer will leave a nice radius on on a Remington 7.5 primer which means you have now transferred the weak link from the primer to the case.
By the time you are getting brass flow into the ejector relief you are now at a pressure that will cause premature bolt failure. And you are really reducing brass life because the primer pockets will loosen very rapidly, sometimes resulting in one, two or three reloads per case before they are toast.
It is also possible to interpret normal shiny spots on the case head as high pressure signs when you still have room to go. This is because it is somewhat normal for the extractor to be at a slightly different hight than the bolt face which rubs the brass surface as the bolt begins to rotate while the case is still at high pressure. This is different than brass flow but I have seen several people think they were too hot and back off with loads that were well under max.
This is why you will hear over and over, never exceed max published loads. The weak link for the Grendel is not the primer or case but the bolt. However bolt failure doesn't reveal over pressure loads immediately unless you are well over max pressures.
It sneaks up on you and then reveals itself as a broken lug.
That's probably more than you wanted to know but it is what I have to share.
Bob