Win 284 - can't reach 2800 with H4831SC without ejector marks

[pat fulghum]

This 7mm Win .284 is new to me, I have been shooting all varieties of 6mm with some success, but to be competitive at long range I feel I really need to get on the 7mm bandwagon.

I have a Krieger 4 groove 32" F-Class gun...
180 Berger Hybrid, jumping .015, CCI BR2 primers, COAL is 3.247.

Chambering has neck at .315, loaded round is .3105 (turned necks), and fired casing are .313.
Loaded with .002 neck tension, and bullets are not hard to seat (30psi with 21st century arbor press with gauge)

I can't get to the 2800 fps+ node.

The barrel now has 200 rounds on it and I thought it might speed up, but it really hasn't

54.6 gr H4831SC is almost there at 2795fps, but I get slight ejector marks. Over 25 rounds, I get 2795 fps, 24 ES, 8 SD, shoots about .33 MOA at 300... good, but not great like my 6BRAI . The ejector marks show up at the end of the 20 shot string.

With H4381SC, Quickload shows 53K psi with max of 63K, so I should I was ok, but the ejector marks are telling me otherwise.

So I thought about trying H4350, thinking that 51.5 was the target, I started "low" at 50.0/50.4/50.8/51.2, but 50.0 gr gave me 2790 and slight ejector marks, I shot all 5 that I had loaded, and put 1 of the 50.4 down the tube (2825fs and hard ejector mark, hard bolt lift) and pulled the rest of them apart. Using, quickload and calibrating the 50.0 gr H4350 to 2790 fps shows 58K psi... too much, and explains the ejector marks)

Do I just have a slow barrel?
Should I try a different primer? I have some CCI 200, and Winchester LR....
Different Powder?

I'm open to any and all suggestions.


- pat

 

[Jay Christopherson]

why do you care about getting to 2800fps or over? Is your current load accurate?

(I'm asking because I know at least one 1000 yard F-Class record was set with a .284 that was running under 2800fps - accuracy, trumps velocity, every time)

FWIW, I don't know that I believe in a "2800+ fps node" per se. I think a node is far more about where your specific barrel likes to shoot at, than any particular velocity. I think there might be a preponderance of barrels that like to shoot in the same general range sure, which gives rise to the notion of a particular velocity needing to be realized. But there's no hard and fast rule requiring it.

Out of 4 .284 barrels that I currently run, 3 like to shoot in the same general velocity range. The other is pretty different... and noticeably more accurate.

 

[gilmillan1]

Stop trashing your brass! Lower your powder charge. No need for 2800+ fps. 50 more fps are not going to win you a match at 1000 yards.

 

[savagedasher]

If you want speed try n550 . Not my powder of choice it hates temperature changes .
Larry

 

[Mulligan]

Tag

 

[Raptor]

Have you tried H000 or 7828 or RL26??

 

[Zero333]

I'd settle at a very accurate slow node. Often I'm more than 100fps slower than a max load and I"m happy. My brass is happy and my barrel is happy.

 

[pat fulghum]

Well, I guess I will stop chasing the 2800-2850 range and just stay where I am. I will report back in a week

 

[coford]

Don't sweat trying to get to 2800+ if its destroying your brass. I have had several barrels that shot great at 2775. Your barrel may also get faster as you go.

I usually have a little better accuracy with H4350 and my barrels like the Hybrids jumped a little further - more like .025 to .030- which might help your pressure situation a little. What twist is your barrel?

 

[pat fulghum]

@Gonzos,
It's a 1 in 9 and 2775 seems good, just getting a bit too much vertical (directly tied to velocity spread as determenied with chrono) for my liking with h4381sc.

With H4350 I will have to stay under 50, but I might give it a shot

 

[Keith Glasscock]

Is this new brass? The increased headspace does some funny things. I don't get ejector marks, but I don't have an ejector either.

I also noticed that your OAL is a little shorter than I would have expected. What is the freebore?

 

[kvd]

I've noticed that with 32 inch barrels, MV seems to be a little slower than can be achieved with 30 inch barrels and the typical faster burning powders. This suggests to me that the pressure may be falling off before the bullet leaves the barrel. Not sure H4350 would help this but slower powders than H4831sc like IMR 7828ssc or H1000 may perk things up. As already mentioned, more jump to the lands might help some with the pressure signs.

My 2¢............................Ken

 

[dragman]

Slightly tighter bore??? Nothing wrong with shooting it under 2800 if it shoots. If you "have to" have move speed change powders. Lots of other powders will give you 2900-2975 with your barrel length and not hurt your brass.

 

[Nowind0]

Pat,
I reread your post and cannot find what brass you are using. I have also heard that Kieger barrels tend to be slower than others (I have no experience with this).

 

[284winner]

If you want the best accuracy, shoot what's accurate. Don't be concerned with fps. If you want fps, shoot RL17. You might get lucky and get accuracy as well. Not likely you'll do as well as H4832/4350.

 

[pat fulghum]

@Keith Glasscock,

Freebore .230, 1.5 degree, 315 neck

This was 2nd load on the brass...
Brass is Lapua 6.5x284 necked up and turned

I do bump the shoulder .002, Redding type S FL sizer and it is not getting sized too much


Attached is a picture of a 500 yard target from the weekend and you can see some vertical. I dropped 2 points at 500 both to vertical. The attached photo is "clean" but you can see too much vertical. That is what I'm trying to get rid of.

 

[dskogman]

Try H4350. It shot better for me at the lower velocity.

 

[pslater]

Have you tried H000 or 7828 or RL26??

+1 on the RL 26

 

[pat fulghum]

I do have 1 lb of RL26, but that is almost as hard to get as H4350....

@dskogman , What velocity and charge are you at with H4350?

 

[geraldgee]

Taken from the article about Reloder 17,

Big Speed Gain with Reloder 17 in .284 Win
RL 17 clearly enables me to run the Berger 180s easily 125-150 fps faster that I normally was able to shoot them with H4350 and H4831SC in this rifle. My previous load ran around 2825 – 2850 fps with the Berger 180s and that was about all I could get out of it.

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