6.5-284 throat growth

[Hengehold]

I will be building a 6.5-284 for the first time. I notice that the case has a short neck. I would like to find out how many shooters seat a 140gr class bullet in front of the neck shoulder junction and out of the potential doughnut area. My initial thought is that the case may not be able to support the bullet if you chase the lands as the throat erodes. Has anyone had an issue with this?

Thanks,
Trevor

 

[.284me]

Non issue for me. I shoot 140 vld's seated way out, using Lapua brass, .290 neck bushing(about .004 neck tension) and graphite lube inside the neck. The bullets stay straight and shoot great. Anneal your cases after a couple firings so they keep the elasticity and you'll be just fine.

 

[DennisH]

I just built one and have the ammo loaded waiting on a good day to break it in.

My bullets are definitely out of the doughnut area.

I loaded 139 Scenars, 140 JLK's, and 142 smk's.

Anneal your cases after a couple firings so they keep the elasticity and you'll be just fine.

FWIW, I anneal every time, just a personal thing. I have been told to watch for carbon as this caliber tends to build carbon up quick.

Dennis

 

[alf]

My reamer with .188" freebore, OAL in the lands .020" or so.

 

[338 Mollett]

Dennis you are advised well,carbon build up is a big issue with that case.I was blowing primers in a match on a load that I reduced by 3g 200 rounds before.

 

[.284me]

I am only pushing mine about 2,870-2,890 fps out of a 27" Lilja 3 grove. That's where my best accuracy is. It seems slow for the amout of powder I'm using compared to other peoples claimed velocitys. But to answer your question on throat growth, I haven't really noticed any after 500 rounds. I can measure my throat when I get home tonight and let you know if you like.

 

[1shot]

My throat got .043 longer in 1,473 rounds. This is driving 140 class bullets at 3,030 fps. using either H-4831sc or N-165. I would need to pull out the reamer to give you the original freebore length, but .188 seems to stick in my mind. That being said I have about 1/3 of the neck left to grip the bullet and it was still giving me a 50% X count then.
Lloyd

 

[expiper]

listen to Loyd,,,do the math,,,I have found most high intensity ctgs, wear the bbl. ~.003 per hundred rounds,,,,,and ,remember the bbl. wears out all the way down also...I have a bbl, tht wuz a 6mm BR for 3200 rounds,,,then re-chambered to .243 win and shot another 2000 rounds,,,,the last dozen shots were like the fourth of July with all the sparks and fire flying down range,,,,,the lands/grooves are almost invisible !!!!,,,Roger

 

[Hengehold]

Thanks everyone. I find it helpful to hear your actual measurements of throat growth. When I was shooting a 6XC I noticed that by 1,000rds my rifle was not grouping like it did when it had a new barrel. I measured the throat and it had grown a substantial amount. for some reason I want to say that the growth was around .800 which seems excessive based on what you all are measuring for the 6.5-284. After adjusting the seating depth to the lengthened throat the groups tightened back up again. after that experience I decided that I would soft seat/jam the bullet in the lands instead of jump it when shooting an Any Rifle. If I did not feel the bullet seat in the lands as I was shooting then I knew the throat had grown again and I needed to adjust. Do the rest of you shoot the 6.5-284 in the lands or do you jump?

-Trevor

 

[338 Mollett]

Depends on the bullet and the barrel.My girl is going fast with 1800 rnds down the tube,but it liked a vld with 10 thou jam.

 

[hogpatrol]

listen to Loyd,,,do the math,,,I have found most high intensity ctgs, wear the bbl. ~.003 per hundred rounds,,,,,and ,remember the bbl. wears out all the way down also...I have a bbl, tht wuz a 6mm BR for 3200 rounds,,,then re-chambered to .243 win and shot another 2000 rounds,,,,the last dozen shots were like the fourth of July with all the sparks and fire flying down range,,,,,the lands/grooves are almost invisible !!!!,,,Roger

That number pretty much mirrors my experience with my one and only 6.5-284. As of 300 rds, it grew .010. I am shooting 130VLDs jammed .010 with Hybrid 100v at 2900. I'm not hammering it either. Shoot one or two and wait ten minutes or'
until the barrel cools down to ambient.