300 win mag reamer

[Broz]

The neck diameter of my dummy rounds with the bergers is .334 however with the 195 Sierras I have it's .337.

If this is true, something is wrong. Both bullets should be .308" and required the same bushing, or loaded neck dia. should be the same, in the same brass.

I suggest measuring again

Jeff

 

[Lonewolf74]

Broz I was thinking the same thing and I'll have to check it all out as I go. I don't know if it would make that much difference but the 5 rounds I loaded with the TMK measuring .337 where in virgin brass. I fire formed these 5 rounds to get some more measurements and ideas. My dummy rounds with the bergers are in these once fired and full length sized brass and I got .334.

 

[Lonewolf74]

Ok I studied the print more and think I'm really starting to understand what I'm looking at and what the measurements are. The neck diameter for the reamer is .3395 which would give me .0055 clearance with my rounds at .334 that part sounds ideal.

I'm still not totally understanding freebore and where I would end up. Going into this I was under the assumption that I want my loaded rounds at 2.925 base to ogive cus that would have the bullet seated in the ideal spot. Now I thought at the same time I want to keep jump or freebore .005-.010. To word it another way my round loaded at 2.925 will be .005-.010 off the lands. Do you actually want to have more freebore than this? Using 2.925 as my base measurement how far off the lands would i be using this reamer? How do I figure this out?

 

[FURMAN]

Mine is 2.933 to the ogive measured with a Stoney Point gauge. As Rhian stated this reamer gives some room to move the bullet. You are not going to get to choose where the rifle likes the bullet to be seated. You will have to vary the seating depth to figure out what it prefers. Mine happens to prefer .040 off. This does seem to be a common distance for the 300 Win with the 215 but like I said there is no guarantee. The piece you may be missing is the leade of the chamber and the ogive of the bullet will affect where the bullet actually contacts the lands.

 

[Lonewolf74]

Yea I'm over thinking it and getting frustrated that I can't totally understand. I've read a lot that claims you don't want to have more than .050 jump but anywhere from 0 to .050 off is where you should find your ideal seating depth. So what I was aiming for is to have my rounds loaded at 2.925 and have no more than .040 jump at this point. So if I happen to find my rifle likes .020 jump my loaded rounds will be at 2.945. Touching lands would be at 2.965.

 

[FURMAN]

I don't want to make your head explode but ignore the comment about not jumping more than .050. My Creedmoor prefers 140 Elite Hunters .080 off. Read Berger's article about VLD seating depth tuning. I have found that most bullets prefer .040 or less in my big game rifles but there is no guarantee.

 

[Lonewolf74]

I don't want to make your head explode but ignore the comment about not jumping more than .050. My Creedmoor prefers 140 Elite Hunters .080 off. Read Berger's article about VLD seating depth tuning. I have found that most bullets prefer .040 or less in my big game rifles but there is no guarantee.

My head won't explode with that. I admit that I'm a novice and I believe all you guy's know better than I do and that I may be looking at this wrong. All I'm trying to do is avoid a lot of freebore that seems to be common with magnum cartridges. In the situation that my rifle ends up shooting best with ogive touching lands I don't want it seated way out

 

[FURMAN]

That "excessive" freebore was for bullets 50 years ago. I would argue that as time goes by and bullets get bigger manufacturers are not keeping up with the times as far as freebore, barrel twist, and magazine length. I can all but guarantee you will be satisfied with the reamer.

 

[Lonewolf74]

Mine is 2.933 to the ogive measured with a Stoney Point gauge. As Rhian stated this reamer gives some room to move the bullet. You are not going to get to choose where the rifle likes the bullet to be seated. You will have to vary the seating depth to figure out what it prefers. Mine happens to prefer .040 off. This does seem to be a common distance for the 300 Win with the 215 but like I said there is no guarantee. The piece you may be missing is the leade of the chamber and the ogive of the bullet will affect where the bullet actually contacts the lands.

So with your OAL at 2.933 your .040 off?

 

[FURMAN]

No, 2.933 is at the lands. My rifle likes Berger 215s seated at 2.893. I am still playing with the load though.

 

[Lonewolf74]

No, 2.933 is at the lands. My rifle likes Berger 215s seated at 2.893. I am still playing with the load though.

Thanks for all the help rf I got it pretty well figured out now. I can't afford to go with a different reamer at the moment but my Smith will set where I want touching lands to be based off a dummy round. I figure 2.935 is the max I would want the bullet seated out before I start to loose bearing surface to neck contact. So ideally throat will be set to where I touch lands at 2.930-2.935 and work backwards from there to find my seating depth sweet spot.

 

[hseII]

I set this reamer up to be easy going, no neck turning and you won't run into issues with any brass, it's not tight anywhere and that is what makes it work well. The freebore is .187 so it gives you just a little room to seat a little of the lands and not put the pressure ring of a 215 Berger beyond the neck. It's proven a solid, easy going reamer.

Updated question-

If my barrel doesn't like the 215 Bergers, how big a deal would that be?

Am I married to the 215 Berger or will Accubonds or the 212 Hornadys al shoot well for instance?

 

[Rjc338]

It is the reamer I used. I would do it again.

I apologize for bringing this back up but this thread was very helpful. So is this reamer more or less freebore than a saami reamer? I am about to build my first custom hunting rifle and I want to get it right. 300 win mag with the 215 Berger. Will this reamer require a extended mag box? If not will that hurt anything? Thanks for your time

 

[FURMAN]

I apologize for bringing this back up but this thread was very helpful. So is this reamer more or less freebore than a saami reamer? I am about to build my first custom hunting rifle and I want to get it right. 300 win mag with the 215 Berger. Will this reamer require a extended mag box? If not will that hurt anything? Thanks for your time

The 300 WM SAAMI chamber is a weird one to me. It has very little free bore(around .012) and it is sloppy. Because of the slop the lead actually allows a 215 Berger to be seated out quit a bit to touch the lands. Rhian's reamer is much tighter for theoretically improved accuracy and has a better freebore/lead. I will have to go look up numbers but I am pretty sure I was still within the 3.7" Rem mag box but mine was a custom action with a Wyatt box installed. The only advantage to a Wyatt box is if you truly need it to allow a bullet to be seated out far enough to reach the lands. If you don't need it it is of no advantage.