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View Full Version : Do I need to re-work this reamer?



Bnhpr
02-22-2008, 11:49 AM
The reamer pictured is a PTG .308 win match. I've had my mic all over it. I'm chambering Krieger 17 twister in HBR contour.

I was told there needs to be no, or little freebore. It appears this is the case.

Where the neck stops, and freebore part of the reamer starts, the reamer is .308. It starts to taper immediately (less than .010) to .300. over a .378 long cutting surface.

Alternately, the 300 mag, and ultr mag above have a longer .308 cutting edge, maybe .100

My 308 reamer should work with the light Berger bullets?

clowdis
02-22-2008, 12:12 PM
Just guessing here, but it sounds like you don't have much if any freebore. That's OK for lightweight bullets or even heavier bullets that are seated deep in the case to where you only have the ogive sticking out the end of the case. You could have a problem with factory ammo in the 150 grain bullet size and up although I doubt you'll be shooting anything that heavy in a 17 twist. If you have a throating reamer you can always push the throat out a little bit if necessary. But it sounds like about what you want for 120-135 gr. bullets.

Rustystud
02-22-2008, 02:37 PM
Dave Kiff list three primary 308 reamers in his chamber drawing book.

1. 308 Winchester (for hunting)

2. 308 Billingsly Palma

3. 308 1995 Palma

The throats are different in all three rounds.

Rustystud

henrya
02-22-2008, 06:20 PM
Why not ask the maker for a print? Then you wouldn't have to guess.

Dave Short
02-22-2008, 06:30 PM
I've had my mic all over it.


You might want to avoid doing that, especially if your micrometer has carbide faces. Your reamer will be happier (therefore, you will be much happier while cutting with it) if you don't direct-measure it's honed cutting edges.

-Dave-:)

PPP MMM
02-23-2008, 01:25 AM
You might want to avoid doing that, especially if your micrometer has carbide faces. Your reamer will be happier (therefore, you will be much happier while cutting with it) if you don't direct-measure it's honed cutting edges.

-Dave-:),,,,,,,,,,,,,,,,,

A print of a drawing and the real thing are two completely different things altogether.
Spare your mic. and make yourself a tool I've described one or two post earlier especially the bushing/stem and it will tell you all what do you want to know about the length of your true freebore.

Shoot well
Peter

Bnhpr
02-23-2008, 08:19 AM
Why not ask the maker for a print? Then you wouldn't have to guess.

I will request one.

I was quite gentle with the reamer, but I can see your point. Although it's not a crystal glass for pete's sake, it's tool steel!

Ben

Al Nyhus
02-23-2008, 08:26 AM
Ben, if you're unable to obtain the freebore info from PTG, you can simply take an old piece of a .30 cal barrel and put in the throat, neck and a bit of the body length...then measure where the lands are with a dummy case/bullet setup.

I'm not sure if you've decided to go with a full length 308W case or if you're going to simply chamber it 'short' and form cases? Is the reamer dimensioned at the rear for Lapua brass? Winchester stuff?

Whatever the case, I would have serious reservations about building a competitive .30 cal. Hunter rifle using a reamer that accomodates unturned necks and with a freebore diameter/length that is not specific to the particular style of bullet you intend to work with. This approach will limit the success of the project from the start and will ultimately prove to be not only frustrating but will never give you the accuracy you need in todays world of Hunter Benchrest competition. The 'old days' of being competitive with .250 groups are long, long gone.

Not trying to be harsh...just honest. :) -Al

Bnhpr
02-23-2008, 12:49 PM
Ben, if you're unable to obtain the freebore info from PTG, you can simply take an old piece of a .30 cal barrel and put in the throat, neck and a bit of the body length...then measure where the lands are with a dummy case/bullet setup.

I'm not sure if you've decided to go with a full length 308W case or if you're going to simply chamber it 'short' and form cases? Is the reamer dimensioned at the rear for Lapua brass? Winchester stuff?

Whatever the case, I would have serious reservations about building a competitive .30 cal. Hunter rifle using a reamer that accomodates unturned necks and with a freebore diameter/length that is not specific to the particular style of bullet you intend to work with. This approach will limit the success of the project from the start and will ultimately prove to be not only frustrating but will never give you the accuracy you need in todays world of Hunter Benchrest competition. The 'old days' of being competitive with .250 groups are long, long gone.

Not trying to be harsh...just honest. :) -Al

Thanks Al,

Freebore seems to be .077"

PTG sent me a drawing, see attached.

henrya
02-23-2008, 05:15 PM
That reamer looks pretty much for shooting bullets normally used in a cross the course rifle (168s or heavier). I think its not right for your purpose.

I suggest you ask Al Nyhus and/or Pete Wass for suggestions as to the dimensions for your re-grind of this reamer to suit the particular bullet you want to use. Nothing like asking someone who's been down the road a few times.

Mike Swartz
02-23-2008, 07:31 PM
Ben;
I see the freebore on the reamer print as .077 as well.What needs to be remembered is the linear tolerances on most reamers is +/-.005 so a .072-.082 reamer could be accepted. Depending on the bullet weight and form this could be quite a lot.

Mike Swartz

Bnhpr
02-29-2008, 11:10 PM
I'm ordering another reamer with no freebore, and a .334 neck, under recommendation of a known HBR competitor.

Ben

Al Nyhus
03-01-2008, 08:35 AM
I'm ordering another reamer with no freebore, and a .334 neck, under recommendation of a known HBR competitor.Ben

Ben, you'll be happy you went this way. :) As we've discussed before, chambering a 308W .165 'short' results in a very good case for Hunter Benchrest competion that works with a bunch of good powders and loves the bullets made on the 1.00" jackets (typically the 118-125 range). Assuming a reasonable 'back end' dimension on the 308W reamer, you'll be able to shorten existing 308W sizing and seating dies for a simple setup.

Keep us up to date on how your project goes. :)

Good shootin'. -Al

Bnhpr
03-01-2008, 08:07 PM
Ben, you'll be happy you went this way. :) As we've discussed before, chambering a 308W .165 'short' results in a very good case for Hunter Benchrest competion that works with a bunch of good powders and loves the bullets made on the 1.00" jackets (typically the 118-125 range). Assuming a reasonable 'back end' dimension on the 308W reamer, you'll be able to shorten existing 308W sizing and seating dies for a simple setup.

Keep us up to date on how your project goes. :)

Good shootin'. -Al

Al,

I bought a Mcmillan edge HBR stock, and was wondering how to inlet the magazine.

My action is a 700 bdl, and has the floor plate.

My question is, should I machine out the stock for a blind mag? or use the floor plate?

If I go the blind option, can I use the spring/box and follower, and just get a separate trigger guard?

Al Nyhus
03-01-2008, 10:14 PM
Ben, do not use the BDL bottom metal...an ADL trigger guard is what you'll want to use.

As for the magazine inlet..since the IBS doesn't mandate that the magazine be functional (able to cycle cartridges), what most people do is just inlet a small magazine cut (long enough to hold whatever cartridge the gun is chambered for) that is deep enough to hold 1 or 2 cases. Ditch the metal mag. box..just get a Davidson single shot adapter and glue a piece of foam to it that rests on the bottom of the mag well. This way, it 'floats' and is moveable when pushed from the top, thereby conforming to all the rules. Getting rid of the sheet metal box and spring/follower assy. does good things for the bedding.

The NBRSA doesn't require a mag. inlet at all..and the single shot follower can be glued to the stock...it just can't be glued to the action, effectively making it into a single shot.

Hope this helps. -Al

Bnhpr
03-03-2008, 03:50 AM
Ben, do not use the BDL bottom metal...an ADL trigger guard is what you'll want to use.

As for the magazine inlet..since the IBS doesn't mandate that the magazine be functional (able to cycle cartridges), what most people do is just inlet a small magazine cut (long enough to hold whatever cartridge the gun is chambered for) that is deep enough to hold 1 or 2 cases. Ditch the metal mag. box..just get a Davidson single shot adapter and glue a piece of foam to it that rests on the bottom of the mag well. This way, it 'floats' and is moveable when pushed from the top, thereby conforming to all the rules. Getting rid of the sheet metal box and spring/follower assy. does good things for the bedding.

The NBRSA doesn't require a mag. inlet at all..and the single shot follower can be glued to the stock...it just can't be glued to the action, effectively making it into a single shot.

Hope this helps. -Al

OK, that simplifies things.

Am I allowed to machine out the stock, and machine/epoxy in an aluminum bedding block for the action, as long as the action can unbolt from the stock?

I have the tools to very accurately fit a block to an action and stock, where I have been only moderately successful in bedding jobs I've tried before, with pillars/epoxt mess.

Ben

will get the davidson.

Mike Swartz
03-04-2008, 09:48 PM
Ben;
If this is to be a legal HBR rifle you are working against a 10# weight limit. That is scope,rings all up ready to go to the line. Depending on the weight of components,scope,stock,rings,etc. this may be pushing things. If you have all the components you can make a calculation and see where you stand. I use pillars in a HBR rifle. A glue in is not allowed. I'd add up the weights and see where you stand.

Mike Swartz

Al Nyhus
03-04-2008, 10:41 PM
Ben, I agree with Mike. An aluminum bedding block is needless weight that does nothing to add to the performance of a Hunter Benchrest rifle. A well done pillar bed job with zero stress is what you're after. The weight a bedding block adds would be better spent in keeping as much of the shank length as possible..effectively giving you a larger barrel profile at the muzzle.

I'd be happy to help you with your bedding when you get to that point, Ben.

Good shootin'. -Al

Bnhpr
03-05-2008, 03:51 AM
Ben, I agree with Mike. An aluminum bedding block is needless weight that does nothing to add to the performance of a Hunter Benchrest rifle. A well done pillar bed job with zero stress is what you're after. The weight a bedding block adds would be better spent in keeping as much of the shank length as possible..effectively giving you a larger barrel profile at the muzzle.

I'd be happy to help you with your bedding when you get to that point, Ben.

Good shootin'. -Al

Thanks Al,

I need to perfect my bedding for sure. I have not added up my weights yet, but thought I could make the block, nearly as light as pillars and epoxy. Probably not. I'll see where I stand. I was thinking I should machine the pillars to match the reciever radius. Some kits I've used are flat.

Ben

Bnhpr
03-05-2008, 04:02 AM
308 Hooper reamer.

How does this look?