Fat bullets and reamer/throat dimension problems

[RAG]

I'm working up specs to have a 223AI reamer made up for me. I know what I want for all dimensions, based on my brass and FL die. However, I'm at a crossroads when it comes the the diameter in the throat/freebore.

You see, I've had problems on two chamberings in a row, a 22BR and 6Dasher, whereby I had throat/FB diameter that was too tight. Once things started getting dirty, the bullet would have to scrape it's way through (I could see scaping on all sides of bearing surface) in order for me to close the bolt; in one instance, it became so tight that it was seating the bullet back due to contact in the throat area (yes, it was very hard to close the bolt). The issue would be expedited when shooting ball powders (faster carbon accumulation in the the throat) and exaggerated when shooting fat bullets (I've found many bullets, especially Vmax, are being made "fat", with a diameter .0003 (or more) greater than other bullets I measure).

In looking for reamer specs for my 223AI, I searched far and wide for reamer prints, including standard 223 reamer prints, to view the throat diameter. I found an equal spattering ranging from .2240 - .2245 (I foundmany at .2240 and .2242); my question is...if you actually get a .2240 or even a .2242 and it "actually" comes out to that dimension, how would you even chamber a bullet as soon as you fire some rounds down the barrel or if you find yourself with fat bullets. I'm perplexed. In the name of chasing accuracy, have we simply gone too far?

This is a varmint chambering, so I was thinking I wanted something more like .2248 (giving me .0008 relief, or .0005 for 53 Vmax I plan to use), but I can't find a single print with a diameter this "large". What am I missing?

Attached are pics of the 53 Vmax measuring .2243 (Note: I have many other 22 cal bullets that measure exactly .2240 with my micrometer)

 

[Jud96]

Call/Email Manson and tell them what you’re doing. I’d do a 0.2248-.225 freebore diameter. A little more clearance won’t hurt

 

[BoydAllen]

Here is something that is worth considering. I think that we all know what a big splash the 6BRAI has made on the long range benchrest scene. The first version that Alex released for the public, that has done very well, has a FB diameter of .244. Personally I think that tight freebores are something that in the past was assumed to improve accuracy. When I asked Alex about the dimension, he told me that they had tested others and went with what worked the best. Years ago I bought some Shilen .22 bullets that were made for them by an outfit in Texas, Outback I think. The pressure rings measured .225.

 

[RAG]

Right. Thank you for the feedback. I can't say I've done any double-blind studies myself, but I've seen/heard nothing about how the tightest possible freebore would improve accuracy; in fact, on my 6Dasher before I had the throat opened up, I felt that it hurt accuracy after 20 rounds or so when the bullets got harder to chamber because there wasn't enough clearance. So maybe it's safe to say that the .0002 clearance "rage" is a thing of the past?

Even if .0002 clearance was slightly more accurate, there would need to be some kind of differentiation between low volume BR use where you can clean in between strings and high volume/varmint use...because I know it doesn't work for that.

 

[urbanrifleman]

I don't know a reamer manufacturer that will claim to hold +/-.0001".

 

[AlNyhus]

I'm working up specs to have a 223AI reamer made up for me. I know what I want for all dimensions, based on my brass and FL die. However, I'm at a crossroads when it comes the the diameter in the throat/freebore.

The 'standard' of .0005 (half a thou) over bullet diameter is most peoples minimum. Almost all bullets will be larger than the bore size, especially across the pressure ring on a flat based bullet. For a non competition rig that will likey shoot a variety of big-box bullets, .0008-.001 over bullet diameter would be a good spot, at least for me.

Keeping in mind that all reamer mfgs work to a tolerance, spec'ing any minimum dimension can get a bit dicey at times. A good approach is on the spec sheet for the reamer, specify your minimum dimension as "Not less than (insert your number here)".

Just my 2 cents worth. -Al

 

[urbanrifleman]

I'm working up specs to have a 223AI reamer made up for me. I know what I want for all dimensions, based on my brass and FL die. However, I'm at a crossroads when it comes the the diameter in the throat/freebore.

You see, I've had problems on two chamberings in a row, a 22BR and 6Dasher, whereby I had throat/FB diameter that was too tight. Once things started getting dirty, the bullet would have to scrape it's way through (I could see scaping on all sides of bearing surface) in order for me to close the bolt; in one instance, it became so tight that it was seating the bullet back due to contact in the throat area (yes, it was very hard to close the bolt). The issue would be expedited when shooting ball powders (faster carbon accumulation in the the throat) and exaggerated when shooting fat bullets (I've found many bullets, especially Vmax, are being made "fat", with a diameter .0003 (or more) greater than other bullets I measure).

In looking for reamer specs for my 223AI, I searched far and wide for reamer prints, including standard 223 reamer prints, to view the throat diameter. I found an equal spattering ranging from .2240 - .2245 (I foundmany at .2240 and .2242); my question is...if you actually get a .2240 or even a .2242 and it "actually" comes out to that dimension, how would you even chamber a bullet as soon as you fire some rounds down the barrel or if you find yourself with fat bullets. I'm perplexed. In the name of chasing accuracy, have we simply gone too far?

This is a varmint chambering, so I was thinking I wanted something more like .2248 (giving me .0008 relief, or .0005 for 53 Vmax I plan to use), but I can't find a single print with a diameter this "large". What am I missing?

Attached are pics of the 53 Vmax measuring .2243 (Note: I have many other 22 cal bullets that measure exactly .2240 with my micrometer)

My 223 Ackley reamer is a bone stock 223 Ackley ppg reamer and it has produced 100 outstanding barrels. I don't think it needs a single change. Ackley knew what he was doing.

 

[RAG]

The 'standard' of .0005 (half a thou) over bullet diameter is most peoples minimum. Almost all bullets will be larger than the bore size, especially across the pressure ring on a flat based bullet. For a non competition rig that will likey shoot a variety of big-box bullets, .0008-.001 over bullet diameter would be a good spot, at least for me.

Keeping in mind that all reamer mfgs work to a tolerance, spec'ing any minimum dimension can get a bit dicey at times. A good approach is on the spec sheet for the reamer, specify your minimum dimension as "Not less than (insert your number here)".

Just my 2 cents worth. -Al

Agreed. It's .001 over bullet for me, I've decided. I just can't believe all the reamer prints that pretty much match bullet diameter in the throat area. Baffles me.

 

[RAG]

My 223 Ackley reamer is a bone stock 223 Ackley ppg reamer and it has produced 100 outstanding barrels. I don't think it needs a single change. Ackley knew what he was doing.

Yeah, I like the sound of that? Do you have a reamer print I can see? I'd love to see where he sets the throat diameter at. Thanks bud!

 

[AlNyhus]

Then again, .3087/.3089 bullets shoot pretty well with a .3085 throat. -Al

 

[Alex Wheeler]

Here is something that is worth considering. I think that we all know what a big splash the 6BRAI has made on the long range benchrest scene. The first version that Alex released for the public, that has done very well, has a FB diameter of .244. Personally I think that tight freebores are something that in the past was assumed to improve accuracy. When I asked Alex about the dimension, he told me that they had tested others and went with what worked the best. Years ago I bought some Shilen .22 bullets that were made for them by an outfit in Texas, Outback I think. The pressure rings measured .225.

And they are in fact all bigger than .244" Some by a lot. I have yet to find a reamer at or under spec. They seem to hit the high side. My best reamer does not measure .244" Its way off that.

 

[Clancy]

I specify a full .001 over bullet diameter.

Freebore is freebore.

If we’ve learned anything from successes in the last few years, it’s that more clearance is often if not always a good thing. More shoulder bump, more neck clearance and larger freebore diameters are the new norm.

 

[RAG]

Thank you gentleman. Coming off two chamberings in a row due to too tight of a throat/freebore area, I'm dead set on not having that issue again. On the chambering with short freebore, the bolt would cam right through the resistance, but on long freebore chambering, things would get progressively worse, and after 40 rounds or so with a little buildup, I couldn't even push the round/bolt far enough forward to get to lugs to cam the cartridge forward.

 

[RAG]

I specify a full .001 over bullet diameter.

Freebore is freebore.

My guess/hunch was that a super tight freebore area was to keep the bullet better aligned on it's passage, lol.

If we’ve learned anything from successes in the last few years, it’s that more clearance is often if not always a good thing. More shoulder bump, more neck clearance and larger freebore diameters are the new norm.

Interesting! I wasn't aware of this. I have my 700 pieces of brass already (for this 223AI reamer)...Im' curious if you think the below dimensions/clearance are about right? I have my brass and my dies, so I was planning on setting dimensions as follows:

.002 over on the web/datum line
.0025 over diameter at shoulder (over the FL sized brass)
.003 over the seated neck diameter (it's neck turned Lapua)
.010 over actual length of my brass
.001 over bullet diameter for the freebore diameter
.020 Freebore (I mostly plan to shoot 53 Vmax, but could mix in some 40-max on rare occasion)

 

[afrench]

...
Interesting! I wasn't aware of this. I have my 700 pieces of brass already (for this 223AI reamer)...Im' curious if you think the below dimensions/clearance are about right? I have my brass and my dies, so I was planning on setting dimensions as follows:

.002 over on the web/datum line
.0025 over diameter at shoulder (over the FL sized brass)
.003 over the seated neck diameter (it's neck turned Lapua)
.010 over actual length of my brass
.001 over bullet diameter for the freebore diameter
.020 Freebore (I mostly plan to shoot 53 Vmax, but could mix in some 40-max on rare occasion)

This...

Call/Email Manson and tell them what you’re doing. I’d do a 0.2248-.225 freebore diameter. A little more clearance won’t hurt

You should call Ray at Manson and talk it through.

 

[Ned Ludd]

I have been shooting .223 Rem F-TR rifles for years that have been chambered with reamers based off PTG's 223 Rem ISSF reamer. These reamers all have a freebore diameter spec of 0.2242" +/- whatever tolerance the manufacturer holds. My experience with the barrels chambered with these reamers is that they have all been stupidly accurate/precise. That is a big part of the reason why I haven't changed that particular spec to a larger dimensions such as 0.2245" when ordering new versions of this reamer with varying freebore lengths to accomodate different bullet weights/lengths. The very tight fit of the bullets is especially noticeable when using a Hornady OAL gauge to find the distance to "touching". The bullets do go into the freebore, but the fit is noticeably tight. In fact, they usually stop moving when they first encounter the beginning of the freebore and you have to push fairly hard on the little plastic stick to get them moving again. It can make the measuring process more difficult, but I don't find it to be a deal breaker. I am almost fanatical about cleaning my competition rifles, so I have never noticed any issues whatsoever with regard to the tight throat and carbon buildup.

I've often thought about going with a reamer that cuts 0.245" -0.247" freebore diameter and spoken in some detail with the folks at JGS about it. The problem with actually doing that is that I know barrels cut with the tighter freebore shoot. Finding out how a slightly more generous freebore diameter would work for my specific shooting purposes would require a new reamer and a new barrel, and at least 6-8 months lead time for the reamer to be made and the barrel to be chambered. So to get a slightly more generous freebore diameter, I'd basically be into the process for somewhere close to $1000 all told, and perhaps upwards of one year waiting time. Given that, I think it is somewhat understandable why the tight freebore .224" reamers continue to be used/propagated. I have not seen much information or feedback posted at shooting forums from individuals using a more generous freebore diameter with very heavy-for-cartridge bullets in the 88-95 gr weight range for use in F-TR loads. If someone has a positive experience using a less tight freebore for such a purpose, I'd love to know about it.

 

[Steve Blair]

I don't know a reamer manufacturer that will claim to hold +/-.0001".

Even if they did, can it reliably cut to that? Likely not.

 

[Clancy]

My guess/hunch was that a super tight freebore area was to keep the bullet better aligned on it's passage, lol.


Interesting! I wasn't aware of this. I have my 700 pieces of brass already (for this 223AI reamer)...Im' curious if you think the below dimensions/clearance are about right? I have my brass and my dies, so I was planning on setting dimensions as follows:

.002 over on the web/datum line
.0025 over diameter at shoulder (over the FL sized brass)
.003 over the seated neck diameter (it's neck turned Lapua)
.010 over actual length of my brass
.001 over bullet diameter for the freebore diameter
.020 Freebore (I mostly plan to shoot 53 Vmax, but could mix in some 40-max on rare occasion)

I’d be lying if I said I’d spec’d anything behind the shoulder. I just tell them the brand of brass I’m using and let them handle that. The rest looks good.

.003 neck clearance when turning, .004 if I want a no turn.

Enjoy that rifle!