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6mm-284 Freebore and OACL Question Help

New to posting but not to this site.
I have been reloading for several years now and most of it was for factory Rem 700s in 223, 22-250,270, 7mm mag, and 300 win mag. Can get good accuracy out of stock guns by bedding, trigger tweeking and precise reloading (several groups under .5 MOA).

My question concerns a gun I just bought from a gunsmith at a show. It is a 6mm-.284. It is a Rem 700 action with a Shilen barrel in 1-12" twist. Smith said to shoot the 68 gr - 80 gr berger bullets that the gun loved them. So after ordering a set of 6mm-284 dies and finding some 6.5-284 Lapua brass I was ready to go last night. Being new to forming wildcats this went very well by just running the 6.5 284 brass thru the 6mm 284 FL resizing die.
When trying to find the lands of the rifling is where I ran into something new. The bullets I have will not reach the lands to set my OACL. I usually start out at .020 and fine tune from there.

Bullets I loaded include Berger 68 gr / Nosler 70 gr / and Watson 75 gr Match

I went forward with the loads by just setting the bullet far enough into the neck that I felt good about controlling runout.

This morning I realized I had a box of 95 gr Noslers and thought I would see if I could find the lands with them. Well I did. The OACL for the 95ers was 3.035 and that was touching into the lands. The 95s will probably not stabilize in the 1-12" twist so I am wanting to make the others as accurate as possible

To the Question

The 95 gr Noslers touched the lands with a OACL of 3.035
The 70 gr Noslers have an OACL of 2.940
Assuming the ogive is the same on these two noslers I am JUMPING bullets .095
The 68 gr berger will probably jump farther depending on the ogive.

IS it OK to jump them that far?
How much can I jump bullets accurately?
Bullets are only seated .09 into the neck Is that enough?
The farther I seat them the more they will jump.

Thanks in advance Looking forward to discussions on this site!!!!!!!
 
If I just had to guess, I would guess that your throat has moved substantially, IF it was originally throated for 68-80gr bullets. You can get by with 85gr Nosler B-tips with a 1-12 twist. However, they might be sitting a bit far off the lands. If you are looking to seat bullets JUST off the lands OR into the lands, you will have to set the chamber back... You CAN jump the bullets a GOOD WAY OFF THE LANDS but who knows how they will shoot. They might BUT they might not..
 
It does sound like your throat has eroded. That caliber will burn out a barrel in no time. 1-12 in a 6mm-284 doesn't make a lot of sense. It is not a BR rifle with light flat base bullets and twist is far too slow for the long heavy 6mms. What are you going to use it for?
 
wboggs said:
It does sound like your throat has eroded. That caliber will burn out a barrel in no time. 1-12 in a 6mm-284 doesn't make a lot of sense. It is not a BR rifle with light flat base bullets and twist is far too slow for the long heavy 6mms. What are you going to use it for?

Depends on what your looking for. I know a couple guys who run them with 13-14 twist barrels. They shoot nosler 55gr ballistic tips really fast. One guy runs them 4300 the other 4400. The drops out to 400 are pretty darn flat. If your looking for a yote gun that you don't have to think about the range it makes sense. Will the barrel last long? NOPE.

Aaron
 
wboggs said:
It does sound like your throat has eroded. That caliber will burn out a barrel in no time. 1-12 in a 6mm-284 doesn't make a lot of sense. It is not a BR rifle with light flat base bullets and twist is far too slow for the long heavy 6mms. What are you going to use it for?

I got it to play with because it was something you don't see often around here, I would like to shoot longer ranges with it and maybe some coyotes or deer. I am going to give it a go tomorrow with the loads I made up last night. If it doesn't suit me a new barrel will be in order to shoot the 105 -115 gr pills.
 
My step father has one in 14 twist. He likes to push small bullets as fast as they will go.
I like the longer heavier bullets for long range groups.
 
Try 87 V-Maxs or 88 Bergers. These are what shoot the best in my 12 twists (YMMV). The base to ogive on mine (87 V-Max) is 2.315 with a COAL of 2.815 with Zero freebore. This puts the base of the BT @ the NK/Shoulder jct. With an 87 V-Max seated out farther you should get much closer to the lands. *Note a longer COAL in a S/A Rem will NOT cycle through the magazine consistantly.
 
FindingCOL.jpg
 
Well after shooting today I think I have a keeper.

My largest 3 shot group was .69 and the best was .33. That was with a 16 power scope so I feel I can do better.I guess it doesn't hurt to JUMP them

It is going to be okay for bullets 80 gr and under.
Not exactly what I want for 600-1000 yds but a good100-400 screamer.

After complaining about the gun to my step father about having to stick with the lighter bullets he sold me his unfired 6.5 WSM. It is also on a Rem 700 action with a Douglas Premium 1-8 twist barrel. Going to shoot 140 grainers out of this one. Cant believe he had this gun in the back of the safe and didn't tell me about it till now
Now I have the best of both worlds
 
One thing I did notice was my cases and bolt were black from leaked gases.
Do you think that I wasn't getting enough pressure to seal the chamber because I had so little bullet into the neck?????
 
Or the Necks have work hardend. Did you anneal after sizing down to 6mm ? I do.
 
I did not anneal. These were brand new Lapua brass and I could see the anneal color on them.
I am going to anneal and try again with the bullet seated a bit further
 
Chappy6mm said:
I did not anneal. These were brand new Lapua brass and I could see the anneal color on them.
I am going to anneal and try again with the bullet seated a bit further

If you didn't anneal them I would not count on it, brand new lapua brass doesn't have any anneal color, 3 lots of them and non has anneal color.
I would anneal it before sizing it down to 6

cases and bolt were black:

I shoot for example the 6.5 284 a lot the only thing that is black after shooting is a bit the neck, however the cases are not nether the bolt. Take the bolt out and look inside the chamber and mouth, is it clean or dark as well? if so clean it up and retry 2-5 rounds. Inspect the area again.

Did you measure the neck expansion of the fired brass is it always the same?

I guess right now that you have issues caused by the sizing of the brass. And I would not shoot to much before fixing it.
 

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