Custom reamers

[DShortt]

I've noticed that there seems to be an attitude that SAAMI spec chamber reamers are inferior in some way. If not directly stated then at least implied.

I understand that if a shooter wants to use a bullet in a weight that is normally considered heavy for the cartridge then a longer freebore might be needed, and I further understand that there are varying opinions on what the optimal leade angle is.

However, apart from those two considerations, what is so inherently wrong with a SAAMI spec reamer provided it cuts a concentric chamber that is not oversize?

Please enlighten me. Serious question.

Thank you for constructive discussion.

 

[Sniperhandle]

There is nothing wrong with them, They used to say you had to have a floating pilot too, Now some guys aren't using a pilot at all.

It was said not too long ago that long throats made for cartridges that weren't too accurate, Now Long throats are the norm so to speak.

 

[TaperPin]

I've noticed that there seems to be an attitude that SAAMI spec chamber reamers are inferior in some way. If not directly stated then at least implied.

I understand that if a shooter wants to use a bullet in a weight that is normally considered heavy for the cartridge then a longer freebore might be needed, and I further understand that there are varying opinions on what the optimal leade angle is.

However, apart from those two considerations, what is so inherently wrong with a SAAMI spec reamer provided it cuts a concentric chamber that is not oversize?

Please enlighten me. Serious question.

Thank you for constructive discussion.

I’m impressed with the wide difference in allowable neck and throat dimensions for any given cartridge. A reamer on the large side, but still within saami specs, is quite large. A saami PRC/Creedmoor/Arc on the minimum side, has much tighter minimum clearances than older designs. Most average shooters don’t understand it and assume one saami cartridge has the same clearance as another saami.

I don’t know how full time smiths keep from pulling their hair out when a 6.5 prc develops issues from improper cleaning causing carbon fouling issues, but the client swears they clean it the same as an old saami 270 with a loose goose neck and throat so the smith must be wrong, or his work is bad. Or insisting on a saami 270 chamber and then complaining it doesn’t shoot as well as that saami 6.5 prc.

 

[DShortt]

I’m impressed with the wide difference in allowable neck and throat dimensions for any given cartridge. A reamer on the large side, but still within saami specs, is quite large. A saami PRC/Creedmoor/Arc on the minimum side, has much tighter minimum clearances than older designs. Most average shooters don’t understand it and assume one saami cartridge has the same clearance as another saami.

I don’t know how full time smiths keep from pulling their hair out when a 6.5 prc develops issues from improper cleaning causing carbon fouling issues, but the client swears they clean it the same as an old saami 270 with a loose goose neck and throat so the smith must be wrong, or his work is bad. Or insisting on a saami 270 chamber and then complaining it doesn’t shoot as well as that saami 6.5 prc.

That is the exact thing I neglected to consider. A specified reamer will cut the chamber to a specific size. A SAAMI spec reamer will cut a chamber somewhere within the tolerance range.

Thank you for pointing that out. It's obvious now that I think about it.

 

[Doug Beach]

That is the exact thing I neglected to consider. A specified reamer will cut the chamber to a specific size. A SAAMI spec reamer will cut a chamber somewhere within the tolerance range.

Thank you for pointing that out. It's obvious now that I think about it.

A properly made and used reamer should cut very close to the print, SAAMI or not. Any reamer maker can provide you with a print for any reamer they make.

 

[jackieschmidt]

A SAAMI SPEC reamer is designed to shoot standard factory ammunition bought anywhere on the planet. Factory ammunition has specific over all lengths so even with heavier and longer bullets for a given cartridge, the rounds can be fired safely from a firearm with a SAAMI chamber for that cartridge.

There is nothing inherently “un precision” about a SAAMI chamber. It can be established with same level of precision as a so called match chamber. It simply has different dimensions to allow the wide variety of Factory ammunition available to be safely used.

 

[DShortt]

A SAAMI SPEC reamer is designed to shoot standard factory ammunition bought anywhere on the planet. Factory ammunition has specific over all lengths so even with heavier and longer bullets for a given cartridge, the rounds can be fired safely from a firearm with a SAAMI chamber for that cartridge.

There is nothing inherently “un precision” about a SAAMI chamber. It can be established with same level of precision as a so called match chamber. It simply has different dimensions to allow the wide variety of Factory ammunition available to be safely used.

I understand. As I said above the detail I failed to consider is with a custom reamer the dimensions can be specified if that is what is desired.

Won't matter in most situations but benchrest is a different game.

Thanks for your reply.

 

[AlNyhus]

Many SAMMI chambers will have a tapered neck of around .001-ish to help a bit with extraction.

 

[moondog]

A good example is the SAAMI 300PRC.
Hornady I believe got that one in the books based on their brass and their 225 ELD.
Works fine with that combo.
Clickers necessitate a different dimension with Lapua.
Freebore is in my opinion too long for Bergers.

 

[urbanrifleman]

Hornady actually got it right, because their Sammi spec reamers for the Creedmoor series of cartridges is actually correct, with the correct free bore.

Most of the time Sammi spec just means an "old spec" . If you get a cartridge that's relatively new, designed for the bullets and brass of the time, you will find that they are actually correct for modern bullets and brass.

 

[Alex Wheeler]

A saami minimum case body is a very good place to start with most cases. In most cases all you need to do is spec the neck and throat you need for your purpose.

 

[DShortt]

A saami minimum case body is a very good place to start with most cases. In most cases all you need to do is spec the neck and throat you need for your purpose.

You've a gift for 'cutting to the chase'. I appreciate the benefits of your experience.

 

[Forpest]

I've noticed that there seems to be an attitude that SAAMI spec chamber reamers are inferior in some way. If not directly stated then at least implied.

I understand that if a shooter wants to use a bullet in a weight that is normally considered heavy for the cartridge then a longer freebore might be needed, and I further understand that there are varying opinions on what the optimal leade angle is.

However, apart from those two considerations, what is so inherently wrong with a SAAMI spec reamer provided it cuts a concentric chamber that is not oversize?

Please enlighten me. Serious question.

Thank you for constructive discussion.

And both of your two considerations can be addressed independently from the chambering reamer. Sammi spec means that the chamber cut with that reamer will chamber any ammo thAT MEETS SAMMI SPEC, - factory ammo. As others have said, ANY well maintained reamer will cut a chamber to the specs of the print; people often think a custom reamer is “better” because it is not SAMMI spec. Reamers are simply tools - used and maintained properly they will cut to the print.

 

[DShortt]

And both of your two considerations can be addressed independently from the chambering reamer. Sammi spec means that the chamber cut with that reamer will chamber any ammo thAT MEETS SAMMI SPEC, - factory ammo. As others have said, ANY well maintained reamer will cut a chamber to the specs of the print; people often think a custom reamer is “better” because it is not SAMMI spec. Reamers are simply tools - used and maintained properly they will cut to the print.

I understand your points but in my limited experience SAAMI spec reamers don't come with a print, they fall somewhere in the tolerance range. Which may be acceptable or unacceptable depending upon the wishes of the shooter.
I think as Alex noted above neck dimensions and freebore length are the primary areas that might cause issues for shooters with specific needs.
Again, my experience is limited and I appreciate the discussion. Always something to learn here. I appreciate the knowledge on this forum.

 

[Forpest]

I understand your points but in my limited experience SAAMI spec reamers don't come with a print, they fall somewhere in the tolerance range. Which may be acceptable or unacceptable depending upon the wishes of the shooter.
I think as Alex noted above neck dimensions and freebore length are the primary areas that might cause issues for shooters with specific needs.
Again, my experience is limited and I appreciate the discussion. Always something to learn here. I appreciate the knowledge on this forum.

A reamer is a tool. All of the reamer maker’s I have worked with can - or do - provide a print to which they build the reamer. Tolerances for manufacturing the reamer are specified on the reamer print. Any reamer - SAMMI or not. I have a notebook full of reamer prints. SAMMI deals with the interchangeability of the ammo - things like pressure, COAL, and other case dimensions. A reamer designed to cut a chamber for SAMMI ammo will be cut to larger dimensions so that the cartridges will chamber without excessive headspace or other dimensions that might cause safety problems. Anyone using a chamber reamer should have the print for that reamer so they know the dimensions of the chamber they will cut. Todays shooters believe, with some evidence, that one can optimize the chamber to shoot specific neck thickness - tight necked chambers - and bullets of a specific length - As determined by head to ogive distance + a certain amount of free bore. many shooter seem to be chasing long for caliber bullets. . There is nothing inferior about a SAMMI reamer or chamber- it is designed to accommodate SAMMI approved ammo for that cartridge, and it is not optimized for that shooter’s particular choice of bullet.

 

[DShortt]

A reamer is a tool. All of the reamer maker’s I have worked with can - or do - provide a print to which they build the reamer. Tolerances for manufacturing the reamer are specified on the reamer print. Any reamer - SAMMI or not. I have a notebook full of reamer prints. SAMMI deals with the interchangeability of the ammo - things like pressure, COAL, and other case dimensions. A reamer designed to cut a chamber for SAMMI ammo will be cut to larger dimensions so that the cartridges will chamber without excessive headspace or other dimensions that might cause safety problems. Anyone using a chamber reamer should have the print for that reamer so they know the dimensions of the chamber they will cut. Todays shooters believe, with some evidence, that one can optimize the chamber to shoot specific neck thickness - tight necked chambers - and bullets of a specific length - As determined by head to ogive distance + a certain amount of free bore. many shooter seem to be chasing long for caliber bullets. . There is nothing inferior about a SAMMI reamer or chamber- it is designed to accommodate SAMMI approved ammo for that cartridge, and it is not optimized for that shooter’s particular choice of bullet.

Ok, so is that reamer print any different than a SAAMI spec print which can be downloaded and printed out? Serious question.

My understanding at this time is if you spec a reamer you get exactly what you asked for. SAAMI has tolerance ranges which are fairly significant in some areas.

If that's incorrect then I can certainly appreciate someone pointing that out. I've never ordered a custom reamer. If there's a tolerance range then that seems to negate the point of a custom in my mind. So it's not an option I'll choose in the future if that's true.

 

[Doug Beach]

Ok, so is that reamer print any different than a SAAMI spec print which can be downloaded and printed out? Serious question.

My understanding at this time is if you spec a reamer you get exactly what you asked for. SAAMI has tolerance ranges which are fairly significant in some areas.

If that's incorrect then I can certainly appreciate someone pointing that out. I've never ordered a custom reamer. If there's a tolerance range then that seems to negate the point of a custom in my mind. So it's not an option I'll choose in the future if that's true.

Everything that is made has a tolerance range. Some are just smaller than others.
I have some SAAMI reamers (JGS & Manson). Their prints show the same tolerances as custom reamers from the same companies. You are not getting some random thing when you order a SAAMI spec reamer. You are getting a reamer, made to the print, within tolerance. Generally, this will be SAAMI minimum dimensions, with tolerances all being +.

 

[DShortt]

I see. So pardon me if I'm splitting hairs, because as I said I've never ordered a custom reamer so perhaps these are dumb questions.

If you order a reamer that specifies a neck diameter, freebore length, throat angle or shoulder angle which varies from SAAMI specs do you still expect the same level of tolerance as the SAAMI tolerance?

Perhaps some reamer makers don't make such accommodations? I honestly don't know.

 

[Doug Beach]

I see. So pardon me if I'm splitting hairs, because as I said I've never ordered a custom reamer so perhaps these are dumb questions.

If you order a reamer that specifies a neck diameter, freebore length, throat angle or shoulder angle which varies from SAAMI specs do you still expect the same level of tolerance as the SAAMI tolerance?

Perhaps some reamer makers don't make such accommodations? I honestly don't know.

You are confusing SAAMI tolerances with reamer tolerances. They are not the same.
A SAAMI reamer is typically SAAMI minimum, -0/ + the maker’s tolerance. SAAMI maximum is not relevant to the discussion.

 

[DShortt]

Interesting you'd say that since I started the thread and the discussion.

So where can I find the published differences that show SAAMI tolerances vs reamer tolerances?