6.5x284 load help

[Jezzro2004]

So this is the second time I've played with working a load up for my Savage predator hunter 6.5x284. This time around I used the following ingredients:
Lapua brass fire formed, uniformed primer pockets, and flash hole.
123 grain Hornady Amax
CCI BR2 primers
IMR4831 powder
Bullets seated .055 off lands due to long throat and shortness of the amaxs
Shot all groups in 91 degree weather letting rifle cool about 10 minutes between each five shot string. Now you experienced people here is some crazy questions, I recently purchased and been loading with the Wilson dies and press.. Most of my velocities and close in one or two groups I've got a really low or high number in some groups which is leading me to believe it could be inconsistent neck tension due to the neck being sized on the outside of brass that has not been turned. Idk... I've also noticed that every round that has been fired in the rifle since I purchased it new, after shooting the spent cartridges neck is so tight that a bullet will not slip down in it. However I have the standard size bushing with my Wilson neck die and it does size the neck back some but it's very minimal. All the groups were shot from a solid bench with front a rear bags. What's everyone's opinion of what's going on based on what you see and hear? What is everyone's opinion on what you would do or try. All powder charged were double checked on rcbs 502 beam scale and on my Hornady auto dispenser/ scale. The rifle has less than 200 rounds through it and was broke in using the shoot one clean, shoot five clean type method. I clean about every 25 rounds now. Rifle has a 20 Moa base, bushnell elite 6-24x50mm scope, Burris rings
Groups are at 100 yards
49.5 gr
2835 (fouler)
2842
2840
2819
2771 (low for some reason)

50.0 gr
2875
2874
2888
2873
2892

50.5 gr
2918
2909
2940
2925
2922

51.0 gr
2940
2945
2953
2914
2995 (high)

51.5 gr
2969
2972
2985
2974
2965

 

[Trnelson]

51.5g shows the least dispersion. I would look first to adjusting the seating depth. It will either improve the group or it won't. From what you posted Something isn't correct with either your chamber or your sizer. That needs to be ascertained prior to going any further.
I would be hesitant to just starting to turn the necks, or ream them in a factory built rifle, without establishing what the chamber dimensions actually are. If a bullet doesn't slide back into a spent case you've got neck diameter things happening. ***BIG RED STOP FLAG WAVING*** either your brass is too thick too long or your chamber neck is too narrow, or a little of both converging. SOMETHING is badly amiss and needs to be corrected prior to firing that rifle again.
I'd be more inclined to looking at inside reaming the brass. A factory chambered SAAMI specification rifle should not require complex brass preparation. Before jumping on brownell's measure the overall length of the case and the neck diameter of a few sized cases and a few spent cases. Measure the thickness of the neck in a few places also on several cases to be sure you have enough material to be able to ream uniformly. Is your rifle chamber 6.5/284 Norma 6.5/284 Lapua or something else 6.5/284 all together? If it is a factory rifle a simple phone call should get you that answer. I would then cast the chamber to see what the chamber neck diameter ACTUALLY measures and compare that to a SAAMI spec chamber. Maybe their chamber reamer was worn out or miss-set or or or. Tolerance stack happens. Then, if the rifle conforms to specification, do the math to establish which combination of reaming, and neck sizing bushings gives you AT LEAST 0.003" of clearance on a fully finished and sized case. I would personally look for 0.005", but that's my opinion and you don't know me from Adam.
I shoot with a guy that has a FULL custom 6.5/284 that he purposely had the neck diameter of the chamber set at 0.294" he NEEDS to ream all of his brass or it simply won't chamber. His spent cases can accept a bullet after fired with very little resistance. I just called him to verify that.
Lasty (which I would check first) does the rifle close on a GO gauge and not close on a NO GO gauge.

 

[Jezzro2004]

Chambering is 6.5x284 Norma, I did some measuring on what I could this morning, I did noticed that some of my cartridge overall length did vary some from what it was most were 2.160" and no more than 2.164 I'd assume that could cause inconsistencies.. My Wilson neck die has a .293 bushing. I tried to post pictures of the brass O.D. Before and after sizing and the spent brass the bullet can be pushed in by fingers but it's kinda draggy. As for neck thickness I'm getting around .0165 -.0170. I don't have a go and no gauge for this caliber. I did post a couple of pics of the headspace on unfired Lapua brass and a round that has been fired 3 times with hot loads if that helps. My unfired brass measured 1.812 and the fired one was 1.8195. I couldn't get all the pics to load from my phone. The brass O.D was .296 before and .294 after sizing

 

[Trnelson]

Nosler lists 2.170" as maximum case length. Published maximum diameter 0.296" loaded case diameter for 6.5/284 norma chambered rifles.
0.0165 + 0.0165 + 0.264 = 0.297" you are crushing the case neck in the chamber. If your brass are 0.0170" thick at the neck it's only worse. I'd say a little inside reaming is certainly in order before continuing to fire those cases.

 

[Jezzro2004]

Okay, maybe this will help out some, I measured the case neck of a loaded round and seems good on that point, I was measuring the case neck thickness with the calipers so that ain't working correctly as a dial indicator would I suppose. Here's the loaded round neck measurement

 

[Trnelson]

Here is how I calculate neck thickness...0.295 - 0.264 = 0.031 / 2 = 0.0155" wall thickness of your brass, in the loaded configuration. 0.295" allows for 0.001" all around the outside of the case once fired, IF your chamber neck is cut 0.297" which is to the minimum side of chamber spec. Your neck bushing is 0.293 so you have decent neck tension. I wouldn't change that just yet. I would look to ream that brass a bit. I would start by taking it to 0.015" that will give you an additional 0.001" total clearance. That will allow the brass to expand and spring back normally. It's still a little to what I consider to be the snug side of things, but you can work with it as long as you know what you have and build your rounds accordingly. Good posting.

 

[243winxb]

Your maximum load of 51.5 should be ok if there are no pressure signs, like hard bolt lift, loose primer pockets, or brass flow into the ejector hole. To improve accuracy i would try a Redding full length sizing type S bushing die and size only 1/2 of the neck. Use about .002" neck tension. On seating the bullet, the neck should expand .002" Control the shoulder set back (head to datum measurement) on sizing, so you feel a slight crush fit when closing the bolt. Test with and without the expander. When using the expander, lube inside of necks and look for a very light drag when the expander pulls thru the neck on each case. I sort brass by weight, using groups sorted by 3/10 gr.

[/URL][/U][/IMG] For me, sizing only 1/2 of the neck makes a difference in accuracy in my Rem 40X. The unsized part expands to the factory chamber after a few firings.

[/URL][/U][/IMG] Bullets jump well to the rifling, so dont have a OAL that is too long. I start with the bullet base (full diameter) at the neck shoulder junction, if it fits the magazine and chamber. If you outside neck turn later, no expander is needed. Brass does not get inside reamed. Just changing bullets can make the biggest difference in accuracy. Berger Bullets have shot well for me in 243 win. Hope this helps. Good luck.