free bore for 284 win

[Swarovski1]

What freebore is needed to shoot 162gr amaxs to 180gr vlds

[6mmBR]

Mines a .214 free bore keeps the bearing surface up above the neck shoulder junction where the .284 is prone to have donuts when formed from Lapua brass. Now you can get Norma brass which is made in .284 so should solve that problem.

[Swarovski1]

Thanks.is yours saami spec or throated longer for vlds.i wanna use 162gr amaxs too

[6mmBR]

No mines a tight neck special for F class. It sits the VLds just above the neck shoulder junction and the hybrids 40-50 thou higher up.

There should be no problems with the A max they'll just sit slightly higher in the neck like the hybrids.

Cheers

Dave

[Swarovski1]

A tight neck as in its reamed smaller then you neck turn, why have a smaller neck when you can have a standard neck then use the s type bushing die to give you the same neck tension, do the cases wear out quicker (split) around the neck from taking brass of it, I am not familiar with neck turning, what is the advantage/ gain from doing this , can it be proven that it makes a difference, regards swaro

[Swarovski1]

Is doughnuts from necking up 6.5x284 lapua cases why you neck turn, I was thinking doughnuts come from necking down, there is alot of info to learn

[Swarovski1]

How much approximately would your 284 f class throat grow after say 1000 firings, I checked the oal of my 6.5 06 tother day and it has grown 50 fow since it was new, I kept the bullet I measured it with to keep an eye on it, ive also checked another load which I thought had grown around 40 fow but I dont think that was the case because they vary considerably between different boxs with different lot numbers, some are more pointed it seems.

[6mmBR]

Donuts are caused as you neck up as thicker shoulder brass is dragged up to form the new larger diameter neck.

When I turn necks I make a cut into the new shoulder area which thins this material down and helps stop donuts forming in the first place.

In my .284 I never altered the seating depth in 2000 rounds it just kept on shooting so never bothered to measure it.

My current WSM has 600 rounds through it and there's no change in seating depth.

[Swarovski1]

I get the necking up now you explained it like that, ive never been one to chase the rifling up the barrel but this time I tried by lengthening ones I had already had loaded with bullet puller then back threw the die at new seating depth, they were no good, I loaded up some more to test with an extra 1.2grs of powder and the same seating depth as the others and they shot into 0.5 inches, I didnt have my usual kit with me so I could sit and test, I had to shoot off the roof of my pickup leaning against the cab, I am confident they will be better when I am steadier, am surprised you dont chase rifling, do you check it at 100yds regularly to see it still shoots small groups

[Brillo]

The throat on my .284 has eroded by 0.005" per 100 rounds.

I would not have known this had I not decided to compare COAL measuring methods. Because I shoot 180 grain VLDs jammed into the lands this means I now check the measurement every couple of hundred rounds. This would also apply if I shot jump sensitive bullets, which the 162 A-Max is in my rifle.

[6mmBR]

If the gun is shooting well what is the point of chasing the rifling?

Our F class target with a 10" bull at 1000 yards will soon tell you if your rifle isn't performing, also continual testing at 100 yards is pointless if things are going well. I would only resort back to this if something was wrong.

I expect why your rounds shot so badly after trying to partly pull bullets and then reseat them was that you altered the neck tension.

When trying to do anything in the accuracy stakes it's always better to start from scratch with things. Also have the best most stable shooting platform possible to run your tests is paramount. Shooting off the bonnet or roof of a pick up the way you mentioned is not going to be conducive to accuracy and brings far to many errors into the equation.

[gbal]

How much approximately would your 284 f class throat grow after say 1000 firings, I checked the oal of my 6.5 06 tother day and it has grown 50 fow since it was new, I kept the bullet I measured it with to keep an eye on it, ive also checked another load which I thought had grown around 40 fow but I dont think that was the case because they vary considerably between different boxs with different lot numbers, some are more pointed it seems.

Neil, "they vary considerably"....indeed they do,as I've said before....main reason COAL is just mischief as a measure to copy etc,if we are into sating depth type numbers....keep the same bullet,use a comparitor-hardly extreme precision but does what it says-compares the same bullet in possibly lengthening throats....it's imprecision is relatively the same each time!Someone else's comparator is probably not the same as yours...so such measures are 'ball park only' across rifles/comparitors etc.

 

Tight necks are not quite as de rigeur as they once were at least in Long Range cartridges...hence too,part of the 'straight 284',straight from the box....probably there is some small gain,perhaps in neck life too-but it's so small compared to the devastation of wind error,that some wonder if it's worth the effort-and the primer pockets tend to go before the case necks anyhow with competition loadings.

For anything other than a dedicated LR competition rig,maybe 100y Bench Rest,tight necks are more faff and fuss than vavavoom-though never underestimate the "feel good/done everything",factor,psychologically. (everything that is,except wind read expertly-which is demanding mental work,not a mechaniical gizmo operation-some of which of course are essential!)

 

Estimated precision gain from bullet pointing,maybe 3%: from wind reading...37%. All those 3%s do help,of course-at the competitive level.

g

[Brillo]

If the gun is shooting well what is the point of chasing the rifling?

 

That's just the point Dave. My 284 likes, and only likes, VLDs jammed into the lands. After about 300 rounds they are just touching the lands and accuracy falls off sharply. Luckily I noticed this in practice and then when I tested differing bullet seating depth methods to determine which one was actually correct I discovered the throat erosion, which I have subsequently monitored.

I'm hoping now that I have a supply of the much revered H4831SC that the throat erosion will reduce or even stop.

 

Of course, another solution is to stop using VLDs altogether and use the Berger Hybrids, which I've found to shoot well at any jump beyond 80 thou (in my gun).

[Swarovski1]

Thanks for all input chaps, ive learnt a lot from this thread, why would h4831sc stop or almost stop throat wear, I do use mainly h4831 and h4831sc,occasionly rel 19 which launches the vlds and hybrids really well, I found n160 was real temp sensitive, what worked well in cool conditions flattened primers and gave a tight bolt in warmer weather.wont use it anymore, got a kilo gathering dust,it might be ok for a back up just incase powder becomes thin on the ground again, need to get a few tubs of sc before shelves are empty, got plenty of the h4831

[Leeman]

The throat on my .284 has eroded by 0.005" per 100 rounds.

 

 

Brillo, mine has gone 28 thou in 500 rounds and like you I'm using VLD's which with this barrel like to be hard into the rifling. The last few shoots including a couple of the F class League shoots I've had too many unexplained elevation shots and couldn't figure out what the problem was until I measured the leade a few weeks ago. Moving the bullet out to suit resulted in a consistent 1/2 - 3/4 MOA elevation spread for a 20 shot group the last time I shot 1000 yards. I've been using Elcho 17 and in an effort to reduce the erosion I've moved to Vit N165, albeit using another 5 grains. I wasn't running the E17 at full tilt so I've pretty much been able to duplicate the velocity I was getting. Whether a bigger case full of a cooler burning single base powder will erode less than the E17 remains to be seen, but I's taught me to measure the leade a bit more often.

 

Richard.

[Swarovski1]

You definately need to pick one bullet and use it to check throat wear.i did do some load testing before I measured it because I didn't have a modified case.sent 2 away to be threaded.once they came back I measured strait away.since then 2 years and around 1250 odd shots the throat has grown 50 fow.all loads jump.30 fow ish.never purposely jammed any.once I made up some 110gr v max loads once using old way to measure using fired case.unloaded after a hunting session and bullet stayed in the bore.case came out and powder went all frew the action down into the trigger.oal gauges and modified cases are essential.

[Leeman]

Swaro,

 

Yes the actual same bullet I used to determine seating depth when the barrel was new. I haven't had any barrel that has eroded this fast.

 

Richard.

 

 

[Swarovski1]

Retested loads at sennybridge today, standing leaning in the fox hole not ideal but it was good enough to cloverleaf them with a rear sandbag, great day, great weather there too,,had 45 shots with my mates 338 lap mag, what a great tool, effortless accuracy at 1450yds, once I got the fall of shot I hit it everytime, loved it.