Getting Carbon on the neck on my reloads

[bonrox]

It's a Lapua 338 and these are my first attempt at reloading. I am getting carbon on the neck when I test shot the loads today. The brass on the left is a Hornady factory load, and the one on the right is my reload. They are both shooting Hornady 250 gr BTHP. Both are starting out .317 neck size and both after fired came out to .323, so the reloads are expanding the same. The reloads are using Retumbo powder. I loaded 91,92,93,94,95 grains (5 of each load) and each test load had the same signs of neck carbon. All 25 shots.

The biggest difference is the OAL for my reloads. When I measured the rifle, I got an average 3.003 with 20 reads over 4 days. It was very consistent. So I took off 5 thousands, .005, and loaded to 2.998. The factory loads have an OAL of 2.94.

The only thing I can figure is that my OAL is too long. Opinions welcome.

 

[WAMBO]

All my reloads with Retumbo look like that but I'm shooting a 300 gr bullet.
When I use H1000 they look more like the one on the left, for a 250 gr bullet I think H1000 would be a better choice but that's just my opinion.

 

[Maxduty]

the Hornady loads are hotter still or have better neck tension I'd guess. Carbon on the neck indicates the gases are getting back that far. the chamber is not being sealed at the neck of your reloads. It indicates a relatively mild load, inconsistent neck tension or really dirty powder. What do your primers look like? I'd load up til pressure signs and see if it's still there.

 

[ken4570tc in WY]

I've seen that before, it's not uncommon especially with slower powders like Retumbo. Even some factory loads have been known to have carbon get onto the necks. I remember Winchester factory ammo doing that. Your case is sealing properly at the shoulder. I'd take WAMBO's advice and step up to H1000. Retumbo may be a little slow for the bullet weight. Shortening your OAL will likely not improve it.

 

[bjay]

Try rl33 its even worst than that

 

[bonrox]

So I loaded some up at the factory Hornady OAL 2.94 and some at 2.95. My thinking is that when the primer gets hit, it is not pushing the case up enough to seal good. If these tests show improvement than I can work the OAL up to where I think it should be and see where the neck carbon starts at. If not, I will get some H1000 and test that.

My first test did show that 91 and 92 grains were the closest group, so I just loaded those 2.

 

[RackOpsTactical]

This is normal, like others have said. Give the chamber a good cleaning and see if that makes a difference.

Use a Tipton # 368628 action and chamber cleaning kit if you dont have one.

 

[flashhole]

I experienced the same thing using Retumbo powder. with my 25-06 and heavy-for-caliber bullets. Accuracy was great but no matter what I did in the process I got sooty necks. A faster powder made the problem go away but I lost in the accuracy department.

 

[Howland]

My brother got carbon deposits on the case necks throughout his .338LM OCW using Retumbo.

I used H1000 in mine and got less than yours at the high end of the OCW, hardly any at the low end.

I'm not too concerned. I'll load for accuracy. If the best load leaves deposits, I'll assume it deposits as much in the chamber necks as the case necks and adopt a cleaning regimen accordingly.

 

[bonrox]

So I got some H1000 and that cut the carbon by about 90%, so I am good to go with that. I ordered some more 250 gr Hornady's and some 285 gr to try with the Retumbo I have left. I ran a 30 round test of 85,86,87,88,90 loads, 5 each. The best groups were the 87, 1 inch group at 200 yds and the 90 with a 1.8 inch group. I still need to deal with OAL adjustments, but at least I have a starting point I can start at..

Thanks to all for the information. I was very helpful.

 

[ken4570tc in WY]

So I got some H1000 and that cut the carbon by about 90%, so I am good to go with that. I ordered some more 250 gr Hornady's and some 285 gr to try with the Retumbo I have left. I ran a 30 round test of 85,86,87,88,90 loads, 5 each. The best groups were the 87, 1 inch group at 200 yds and the 90 with a 1.8 inch group. I still need to deal with OAL adjustments, but at least I have a starting point I can start at..

Thanks to all for the information. I was very helpful.

Good to know the H1000 took care of the issue.

 

[918v]

Just wait till you find a ding in the case body.

 

[wilson1911]

Whats your neck tension ? Too little can give carbon on the necks also.

 

[bonrox]

I don't think the neck tension is an issue. From what I can detect, it is about .002.

I am going to try some 285 gr bullets with the Retumbo and see if that makes a difference as well.

 

[bax]

Why do you care about the carbon on the neck?

 

[Eddystone]

No matter what, with these powders, clean your chamber and throat very frequently. That carbon will create a carbon ring slowly and then critical build up happens. That is when frustration starts. Had on in my rifle KICK my butt. Had a hell of a time getting it out. Rifle works as normal now. I "think" light loads with the Retumbo is what got it started for me. Good stuff, just need maintenance with it. Good shooting

 

[Matches Malone]

Sounds like a sign of over pressure or you are trimming the neck to far down.
Those were what happened to me the two different times I experienced such.