Barnes TTSX-BT 140gn 7mm-08

[7mm-08]

I get limited range time so I was planning on just using 150 ELD-X in the Hornady Precision Hunter. They do ok in the gun.

It’s kind of late for this season, but I started working up a new load today. 140 TTSX-BT over A2700. I started at 45gn and went to 48.5gn in .5gn increments. I’m at reliable functioning mag length which is 2.843 COAL.

My crude method of finding the lands was loading a bullet a little long until I could just jam the bolt closed and seat the bullet the rest of the way, then, with a new bullet seat it to that length and try closing the bolt, bump the bullet back, try the bolt, bump the bullet, try the bolt…until I could close the bolt without resistance. Although, that’s not precise, is gives me an idea of the lands for a bullet that generally doesn’t want to be on the lands anyway. The bolt closed smoothly at 2.879. So, mag length is about .036 off the lands.

We will start there and see what happens.

I’ll return with an update.

 

[Addicting]

Barnes recommends starting at .050 off the lands. I have found that to be the best starting point. They have never shot good any closer. Then go to .030 difference in testing depth.

So I normally do .050, .075, & .100. Normally one shoot the best by far and that is what I run.

 

[MThuntr]

A quicker way is to drop a cleaning rod down a closed empty chamber and then on one with a bullet lightly touching lands. Marking both and measuring the distance between the 2


Really just buy the comparator tools since once you start reloading you'll want one anyway

 

[Dougfirtree]

That's a good bullet and you have to work with what you can get these days. That said, if I were going to start working on a Barnes bullet for the 7mm-08, it would be the 139 grain LRX.

 

[7mm-08]

I had my hands on some 139 CXs today but didn’t buy them since I had 6-7 boxes of the Barnes already that I’d bought a while back.

 

[std7mag]

Don't size your neck so tight next time.
You could have just measured after you got the bolt closed and taken 0.050" off.

 

[D4570]

I'm all in on Barnes not that I have to but I want to.
Everything from 17 cal to 338/378 Many different chamberings.
BUT DON'T CROWD THE LANDS.
They shoot WAY better backed off to AT Least .030 even more on most.

 

[7mm-08]

Bumped them all back to .50 off the lands.

Shot this morning. Started with 45gn of A2700. Went to max looking for pressure signs.
Very faint extractor marks at 47gn. Bolt stated getting snug at 47.5-48. Blown primer at 48.5gn.

Went back to 45.5 and 46.5gn.

I guess in need to keep it at around 46.5gn.

What’s next?
1) Bump it back another .030” and try 45-47 again?
2) Load 45.5-46.75 in .25gn increments?
3) Load up 40 at 46.5 and see if it was a fluke.

 

[7mm-08]

 

[7mm-08]

I see the primers getting flatter, but no real residue around the primers. An occasional light extractor mark, but nothing you could feel or catch on a fingernail.

 

[7mm-08]

Shot 3 fouling shots, then a 10 shot group. The two lower ones definitely had a different cheek weld on them. I had my head slightly higher on those two shots, if that makes a difference. The far right shot was the last shot, so I’m going with, passed the sweet spot on the fouling. I’m just making excuses now. The overall is 1.485, but the cluster of 7 shots is .83”. Occasional light extractor marks, bolt opened freely.

I also tried some set at .080 back and 47 gr. They had fouling around the primer and the fourth one blew the primer. The bolt was a little snug opening them up, so I’ll just unload the rest of them.

I jumped back to some at 46.2 @ .050 to see how they compared to the 10 shot group. That’s lighter than the 10 shot group. First shot blew the primer.

I shot a bunch of factory stuff with 4-5 shot groups hitting at 1.5-2” groups.

This is all the same brass I shot yesterday. Yesterday the 47.5-48.5 had an increasingly tight bolt. Did I ruin this brass and loosen up the primer pockets, and should just scrap it and try the 46.5 @ .050 again with fresh brass, or am I just too hot and too close? It’s not a bad group.

 

[Addicting]

Your chasing your tail. Do one thing at a time! You don’t know what works when you change 2 things at once. Plus shooting that much in a session your results will be skewed from the barrel heat unless your letting it cool 5 or so min across shots. Which I am guessing why your blowing primers at safe load levels. If it’s heating up the cartridge you velocity is going to have wild spreads.

I would switch powder to big game or Varget. Then load 10 rounds at .2g increments and shoot it across a chrono. Find the velocity node where 3 are within 15fps-20fps.

Then work on seating depth and groups.

 

[7mm-08]

Your chasing your tail. Do one thing at a time! You don’t know what works when you change 2 things at once. Plus shooting that much in a session your results will be skewed from the barrel heat unless your letting it cool 5 or so min across shots. Which I am guessing why your blowing primers at safe load levels. If it’s heating up the cartridge you velocity is going to have wild spreads.

I would switch powder to big game or Varget. Then load 10 rounds at .2g increments and shoot it across a chrono. Find the velocity node where 3 are within 15fps-20fps.

Then work on seating depth and groups.

I ripped off three fouling shots, then set up the range and let the gun cool. It probably took an hour to shoot that 10 shot group. I may have sped up a little after that, but didn’t get smoking hot.

I’m not dismissing anything anyone says here. I have one kind of primer and a couple kinds of powder.

I have IMR 4350, IMR 4064 and H335. None of them were on the Barnes list so I had to hunt and peck until I found something on their list. I’ll be happy to try a different powder if I find some.

Don’t have a crono, probably need to get one.

Checked headspace today. I shoot a a gunsmiths house. He’s not really a reloader, so he didn’t have mush to say about the load other than the headspace is fine.

 

[JT88]

The 46.5 gn group looks like a winner for hunting. If you don't have a reliable chrono to check your SD there's not much point in tweaking recipes. At some point you're just wasting hard to find pills... .7 MOA will do the job as well as .5 MOA will for hunting purposes. Indeterministic variables will take a way larger toll in the field than the .2 MOA difference. Consistency > Velocity, Reliability > Chasing the lands

Don't get me wrong, I like seeing how well a rifle will shoot too, but with hunting ammo there's a point of diminishing returns

 

[Addicting]

I ripped off three fouling shots, then set up the range and let the gun cool. It probably took an hour to shoot that 10 shot group. I may have sped up a little after that, but didn’t get smoking hot.

I’m not dismissing anything anyone says here. I have one kind of primer and a couple kinds of powder.

I have IMR 4350, IMR 4064 and H335. None of them were on the Barnes list so I had to hunt and peck until I found something on their list. I’ll be happy to try a different powder if I find some.

Don’t have a crono, probably need to get one.

Checked headspace today. I shoot a a gunsmiths house. He’s not really a reloader, so he didn’t have mush to say about the load other than the headspace is fine.

46.5 is over pressure then. Looking at your primers there is a ring around the firing pin. That is the wrong powder for your rifle. I would stop and find a different powder. Just cause one isn’t listed doesn’t mean you can’t use it. Attached is a List of powders that you can use to substitute based on burn rate. IMR4350 is right next to a2700 so they are mostly interchangeable. Start at the min and work your way up.

 

[Addicting]

The 46.5 gn group looks like a winner for hunting. If you don't have a reliable chrono to check your SD there's not much point in tweaking recipes. At some point you're just wasting hard to find pills... .7 MOA will do the job as well as .5 MOA will for hunting purposes. Indeterministic variables will take a way larger toll in the field than the .2 MOA difference. Consistency > Velocity, Reliability > Chasing the lands

Don't get me wrong, I like seeing how well a rifle will shoot too, but with hunting ammo there's a point of diminishing returns

If he blew a primer at 46.2 he is over pressure.

 

[JT88]

If he blew a primer at 46.2 he is over pressure.

Sorry I missed a few posts and pictures there. Only saw the one blown primer at 48.5. I'm confused by the sequence of this whole thread, disregard my post. And that 10 shots 1.5" group too - I agree with @Addicting you need to start over with a better suited powder

 

[7mm-08]

I don’t mean to keep dodging the pressure issue. I was clearly all over it yesterday before backing down on the powder, but I want to address the question in post 11.

If I flat out abused some brass yesterday, cleaned and resized it last night, loaded it back up this morning and shot it again, could this load be in the upper end of acceptable but the brass from yesterday isn’t holding primers? I know some of that brass already had flattened primers, soot rings, and sticky bolt opening from yesterday. I may have had a different result had I just tossed that lot rather than cleaning it.

Yesterdays primer at 48.5, I have no idea where it went.

The two today, we’re intact, and rolling around in the gun when I extracted the spent case. They just looked like the fell out. Perfect condition, just no longer in the case. I have no idea how that happened unless it stuck to the bolt when the ejector kicked the brass away from the extractor. That’s why we checked head space.

( I kinda remember when priming them last night a few times being like, “Oh, that one went in easy” and others I squeezed in. )

As for the roll around the firing pin…I get that on factory ammo of all kinds. I’ve read that the firing pin hole may be oversized, and part of the thin primer metal is squeezing between the pin and the hole.

Factory Hornady Precision Hunter shot today. Factory loads with no other signs. Norma Whitetail does it too.


I don’t want to be the guy that asks a question, then doesn’t like anyones answer. I just want to be thorough.

Thank you all for helping me sort through this, maybe I should have included more info from the start, maybe you’ll tell me I’m smoking crack, because brass is either good or it’s split. These reloads are all once fired factory, twice fired yesterday, third firing today.

 

[Addicting]

If you stretched the primer pocket out on 1 firing to cause them to fall out your chamber is oversized allowing the head to expand in diameter. Very hot loads will kill brass quick but you get more than one reload even with hot loads.

That is the wrong powder and primer combo for your gun.


Also those look like Winchester primers. If so they are likely part of the problem. They have been known to have consistency issues of hot primers.

Federal or CCI is where I would stay.

 

[7mm-08]

Thanks Addicting.
They are Winchester. I’ll look for some other primers and powder.