RF reamer for sk ammo

[tim]

Lee,

I've read that "optimized" for Lapua before, but I don't understand what it means.

I understand how the action can dictate how a certain chamber will work best.

But the word "Optimized" infers they are doing something different just for Lupau ammo. If they are I would like to know what it is.

This goes back to when many RFBR shooters changed from Eley to Lupau. I was one of them.

I simply bought some lots of Lapua and started shooting it out of the same rifles/chambers I had been using.

My scores improved and went back to the levels of 2014 and earlier and it was much easier to find good lots that worked in my rifles.

Then I started hearing this "Lapua" chamber thing and I wondered if I should be doing something different.

One difference between Eley and Lapua is the rim thickness.

Lapua normally has a little thicker rim. For that reason, I changed headspace from .042-.043 to .044-.045.

Then I experimented with various chamber depths, straight sided vs tapered chambers, 1.5-, 2-, and 3-degree leade angles, etc. etc.

Looking at the reamers I defy anyone to look at them and tell which angle they are. A 1.5 degree vs a 3 degree is really small and a 1.5 vs 2.0 is ridiculous. As far as I can tell it was wasted money.

Until this day I haven't found anything that improved Lapua that didn't have the same effect on other ammos.

This goes back to Chris's question asking about SK ammo and I'm asking about Lapua in general.

If someone has found the secret sauce, please share.

TKH

Yep, kind of where I came down.
One question if you wish to share, did you find the need to re tune for Lapua? I have yet to personally determine that aspect.

[tonykharper]

Yep, kind of where I came down.
One question if you wish to share, did you find the need to re tune for Lapua? I have yet to personally determine that aspect.

Tim,

I may not be the best person to ask about tuning. But to answer your question, no. The same tune seemed to work for me.

It has been a long time since I expected tuner turning to do much for my accuracy.

I consider tuning to be critical, but the tuning I'm speaking of has very little to do with dialing the tuner itself.

It is more to do with lug contact, trigger timing, firing pin fall, bedding, and fitting of various parts.

Once I get this right, I find dialing the tuner a fairly quick and easy process.

I do get frustrated sometimes and reach up and turn that thing, but it rarely solves my issue.

I'm not saying tuners don't work, of course they do. What I'm saying is there are many other things that can cause a rifle not to shoot well and those need to be addressed first, or you are just wasting ammo.

TKH

[kevinnevius]

All:

The “optimization” is simply using chamber depth (and therefore bullet seating depth) to optimize ammunition performance. Anyone who develops loads for CF competitions knows how important bullet seating depth is – IMHO, it is one of the most influential – so it made sense that some experimentation with RF might be beneficial to performance.

During two seasons I chambered several barrels, and incrementally moved the position of the lead to try to determine if (1) there was a quantifiable improvement, and (2) if that improvement was consistent across multiple barrels and potentially multiple barrel configurations.

I found a position that I believe optimized performance with Lapua ammunition, and published it for whomever might be interested. In the many seasons since, I have retested my findings and have not found a better position – I continue to use it to this day. Is it perfect? No, but RF competition and smithing is a continuous search for something better. I simply published what I had found.

I was fortunate to have many conversations with the finest RF gunsmith or our era – Mr. Karl Kenyon. His preference was the 1.5 degree leade angle chamber, and given all of the ammunition suppliers of his day produced round nosed ammunition, it made sense to me to use it in my testing. No other reason – just absolute respect for Karl and his opinion (backed by virtually thousands of the most successful rifles in existence).

And I never said Lapua doesn’t run exceptionally we in 2 degree chambers – I won my first National Championship with it in a 2 degree chamber. I was simply experimenting to find something better.

This thread explains it better than a short paragraph here FYI.

https://www.rimfireaccuracy.com/Foru...pua-use.23372/

Maybe some of the confusion is due to my residency outside someone’s inner circle – if such a thing existed of course.

All the best,

kev

[Jerry H]

With your ".660" depth, what is the stick out dimension from the back of the rim to the barrel or from the front of the rim to the barrel?

[tonykharper]

All:

The “optimization” is simply using chamber depth (and therefore bullet seating depth) to optimize ammunition performance. Anyone who develops loads for CF competitions knows how important bullet seating depth is – IMHO, it is one of the most influential – so it made sense that some experimentation with RF might be beneficial to performance.

During two seasons I chambered several barrels, and incrementally moved the position of the lead to try to determine if (1) there was a quantifiable improvement, and (2) if that improvement was consistent across multiple barrels and potentially multiple barrel configurations.

I found a position that I believe optimized performance with Lapua ammunition, and published it for whomever might be interested. In the many seasons since, I have retested my findings and have not found a better position – I continue to use it to this day. Is it perfect? No, but RF competition and smithing is a continuous search for something better. I simply published what I had found.

I was fortunate to have many conversations with the finest RF gunsmith or our era – Mr. Karl Kenyon. His preference was the 1.5 degree leade angle chamber, and given all of the ammunition suppliers of his day produced round nosed ammunition, it made sense to me to use it in my testing. No other reason – just absolute respect for Karl and his opinion (backed by virtually thousands of the most successful rifles in existence).

And I never said Lapua doesn’t run exceptionally we in 2 degree chambers – I won my first National Championship with it in a 2 degree chamber. I was simply experimenting to find something better.

This thread explains it better than a short paragraph here FYI.

https://www.rimfireaccuracy.com/Foru...pua-use.23372/

Maybe some of the confusion is due to my residency outside someone’s inner circle – if such a thing existed of course.

All the best,

kev

Kevin,

Thanks for sharing that information.

So, what you found at .660 took out the vertical on your two barrels even though they had a different number of grooves.

How many different brands of ammos did you try at that depth? Or did you only test Lapua?

In my experiments with chamber depths, I really could not tell it effected Lapua any differently than it did Eley. When I reached what I thought was my best depth it seemed best for both.

We both used spiral cut reamers. I have 1.5, 2.0, and 3.0 and as long as engraving is the same, I did not see a problem with vertical. But I could see a difference when I changed the depth as you did, but in the other direction.

As you said our experiments were so limited, they may not actually prove much.

BTW: Do you finish your chambers, or do you leave them as reamed?

TKH

[Hi-NV Shooter]

Yep, kind of where I came down.
One question if you wish to share, did you find the need to re tune for Lapua? I have yet to personally determine that aspect.

Tim, I am wondering what would be that much different from Lapua than Eley that would cause an out of tune? I see this brought many times IMO could it be the bullet shape and how it affects engraving which make it seem like it is out of tune?

IME, I seen that with more engraving lot selections becomes really critical. since using the 1.5 degree and chambered how Kevin had found works best and to be honest, I really need to look using a loupe to see any engraving. lot selections are not as critical. I believe for most who use off the shelf barrels meaning you order it, and the smith slugs then chambers it without any more hand lapping it is the easiest way to get good shooting results.

Lee

[tim]

Lee,
I am wondering as well, thus my question. I too have seen it referenced but, myself, I’m at the same for both for now. This spring, without going nuts, I will test a bit further.

[Hi-NV Shooter]

Lee,
I am wondering as well, thus my question. I too have seen it referenced but, myself, I’m at the same for both for now. This spring, without going nuts, I will test a bit further.

Tim, I have a barrel that I believe was a little tighter in the bore size then I have seen before had it chambered like other barrels and engraving was just pass the first band.it shot really fantastic.
But was very erratic had the chamber deepened another .0025 that made all the difference it became more consistent. and not finicky on the lots it would shoot. and engraving is about 0.030 on the first band.

Just a thought I wonder how much engraving those top line air rifle have I know those things can shoot!

Lee

[kevinnevius]

Kevin,

Thanks for sharing that information.

So, what you found at .660 took out the vertical on your two barrels even though they had a different number of grooves.

How many different brands of ammos did you try at that depth? Or did you only test Lapua?

In my experiments with chamber depths, I really could not tell it effected Lapua any differently than it did Eley. When I reached what I thought was my best depth it seemed best for both.

We both used spiral cut reamers. I have 1.5, 2.0, and 3.0 and as long as engraving is the same, I did not see a problem with vertical. But I could see a difference when I changed the depth as you did, but in the other direction.

As you said our experiments were so limited, they may not actually prove much.

BTW: Do you finish your chambers, or do you leave them as reamed?

TKH

Good morning Tony:

All of this happened in the first few years of my sponsorship (around 2011 I think), so to answer your question - no, I did not run any testing with Eley (or any other manufacturers ammunition). I have to believe that it would make a difference though, just based on what I saw initially and in all the barrels / seasons since.

From memory, I ran the initial testing with two older Hart barrels I horded (that were six groove .2170 / .2220 barrels). Since I have retested with everything I had - Benchmarks, Kriegers, Shilens (Octagons and Ratchets) and a very few Muller 8 groove blanks. Although the engagement depth preferences varied slightly, there has always been a "sweet spot" where group size and vertical dispersion leveled out, and that accuracy was maintained through 200+ rounds without cleaning (I don't like cleaning between individual matches at our events).

And I have never tried to establish a dimension from the datum (the .660" you mentioned) - when chambering, I use a number of live rounds, cleaned of lubrication, very gently seated against the leade until you can feel them make a hard stop. I then measure what Jerry calls the "stickout", or the distance from the back of the cartridge to the tennon datum face. That dimension minus headspace gives you engagement depth. I currently use the same setup found in the initial testing I ran of .0780 (minus .0430 HS) for an engagement depth of .0350 approx. Lapua ammunition is amazingly consistent round to round, and you would be amazed how repeatable this dimension is between rounds. Lead is soft, so I don't use the same round twice during verification (just in case there is a small amount of deformity). You can definitely feel a hard stop as the round seats against the leade.

Although I have never run this testing with Eley, I do have a "standard" Eley chamber I use (I shot Eley in competition my entire career prior to 2008, and was doing my own smithing at that time too). The chamber setup I use for Eley engraves with a "stickout" dimension of approximately .1360 (approx. .0930 engraving). I say approximately because I have found Eley far less repeatable round to round regarding the distance to the driving band. That's not a knock on Eley (we all know it shoots exceptionally well), it just doesn't allow measurement in this way without some bracketing. Just wanted to share what I was doing for Eley on the rare occasion I do a barrel for it. BTW.....Lapua in the same chamber engraves to a "stickout" depth of .1170 (Lapua's driving band position is shorter / smaller than that of EPS, about .0190).

I have tried a million chamber finishing methods - mandrels, lapping compounds, you name it. In the end (and please, this is only my opinion) I just couldn't justify putting anything even mildly abrasive in a chamber I have tried so hard through the machining process to be dimensionally perfect and concentric. So I have concentrated on speeds / feeds and lubrication to try to machine the most clean / smooth and burr free chambers I can - and let the round count do the rest. If you are interested, I use JGS carbide reamers, at 180rpm, fed exceptionally slow (cleaning chips every .100, and .030 on the last pass) with the older (non EPA compliant) tap magic fluid. Not sure what is in that stuff, but it cuts exceptionally clean chambers with sharp tools. I chamber in a steady rest from the tailstock. There are a million ways to do it, and again, not saying this is the best way (it's just the best way I've found, for my equipment).

I hope I answered your questions, thanks for the reply,

kev

[tim]

Tim, I have a barrel that I believe was a little tighter in the bore size then I have seen before had it chambered like other barrels and engraving was just pass the first band.it shot really fantastic.
But was very erratic had the chamber deepened another .0025 that made all the difference it became more consistent. and not finicky on the lots it would shoot. and engraving is about 0.030 on the first band.

Just a thought I wonder how much engraving those top line air rifle have I know those things can shoot!

Lee

Did you happen to monitor how fast it built carbon in the throat before and after?

[Hi-NV Shooter]

Did you happen to monitor how fast it built carbon in the throat before and after?

Sorry I didn't. but FWIW I run a wet pellet every 30-50 rds. or every card I shoot.

Lee

[Hi-NV Shooter]

Good morning Tony:

All of this happened in the first few years of my sponsorship (around 2011 I think), so to answer your question - no, I did not run any testing with Eley (or any other manufacturers ammunition). I have to believe that it would make a difference though, just based on what I saw initially and in all the barrels / seasons since.

From memory, I ran the initial testing with two older Hart barrels I horded (that were six groove .2170 / .2220 barrels). Since I have retested with everything I had - Benchmarks, Kriegers, Shilens (Octagons and Ratchets) and a very few Muller 8 groove blanks. Although the engagement depth preferences varied slightly, there has always been a "sweet spot" where group size and vertical dispersion leveled out, and that accuracy was maintained through 200+ rounds without cleaning (I don't like cleaning between individual matches at our events).

And I have never tried to establish a dimension from the datum (the .660" you mentioned) - when chambering, I use a number of live rounds, cleaned of lubrication, very gently seated against the leade until you can feel them make a hard stop. I then measure what Jerry calls the "stickout", or the distance from the back of the cartridge to the tennon datum face. That dimension minus headspace gives you engagement depth. I currently use the same setup found in the initial testing I ran of .0780 (minus .0430 HS) for an engagement depth of .0350 approx. Lapua ammunition is amazingly consistent round to round, and you would be amazed how repeatable this dimension is between rounds. Lead is soft, so I don't use the same round twice during verification (just in case there is a small amount of deformity). You can definitely feel a hard stop as the round seats against the leade.

Although I have never run this testing with Eley, I do have a "standard" Eley chamber I use (I shot Eley in competition my entire career prior to 2008, and was doing my own smithing at that time too). The chamber setup I use for Eley engraves with a "stickout" dimension of approximately .1360 (approx. .0930 engraving). I say approximately because I have found Eley far less repeatable round to round regarding the distance to the driving band. That's not a knock on Eley (we all know it shoots exceptionally well), it just doesn't allow measurement in this way without some bracketing. Just wanted to share what I was doing for Eley on the rare occasion I do a barrel for it. BTW.....Lapua in the same chamber engraves to a "stickout" depth of .1170 (Lapua's driving band position is shorter / smaller than that of EPS, about .0190).

I have tried a million chamber finishing methods - mandrels, lapping compounds, you name it. In the end (and please, this is only my opinion) I just couldn't justify putting anything even mildly abrasive in a chamber I have tried so hard through the machining process to be dimensionally perfect and concentric. So I have concentrated on speeds / feeds and lubrication to try to machine the most clean / smooth and burr free chambers I can - and let the round count do the rest. If you are interested, I use JGS carbide reamers, at 180rpm, fed exceptionally slow (cleaning chips every .100, and .030 on the last pass) with the older (non EPA compliant) tap magic fluid. Not sure what is in that stuff, but it cuts exceptionally clean chambers with sharp tools. I chamber in a steady rest from the tailstock. There are a million ways to do it, and again, not saying this is the best way (it's just the best way I've found, for my equipment).

I hope I answered your questions, thanks for the reply,

kev

Great information Kevin!

Lee

[tonykharper]

Good morning Tony:

All of this happened in the first few years of my sponsorship (around 2011 I think), so to answer your question - no, I did not run any testing with Eley (or any other manufacturers ammunition). I have to believe that it would make a difference though, just based on what I saw initially and in all the barrels / seasons since.

From memory, I ran the initial testing with two older Hart barrels I horded (that were six groove .2170 / .2220 barrels). Since I have retested with everything I had - Benchmarks, Kriegers, Shilens (Octagons and Ratchets) and a very few Muller 8 groove blanks. Although the engagement depth preferences varied slightly, there has always been a "sweet spot" where group size and vertical dispersion leveled out, and that accuracy was maintained through 200+ rounds without cleaning (I don't like cleaning between individual matches at our events).

And I have never tried to establish a dimension from the datum (the .660" you mentioned) - when chambering, I use a number of live rounds, cleaned of lubrication, very gently seated against the leade until you can feel them make a hard stop. I then measure what Jerry calls the "stickout", or the distance from the back of the cartridge to the tennon datum face. That dimension minus headspace gives you engagement depth. I currently use the same setup found in the initial testing I ran of .0780 (minus .0430 HS) for an engagement depth of .0350 approx. Lapua ammunition is amazingly consistent round to round, and you would be amazed how repeatable this dimension is between rounds. Lead is soft, so I don't use the same round twice during verification (just in case there is a small amount of deformity). You can definitely feel a hard stop as the round seats against the leade.

Although I have never run this testing with Eley, I do have a "standard" Eley chamber I use (I shot Eley in competition my entire career prior to 2008, and was doing my own smithing at that time too). The chamber setup I use for Eley engraves with a "stickout" dimension of approximately .1360 (approx. .0930 engraving). I say approximately because I have found Eley far less repeatable round to round regarding the distance to the driving band. That's not a knock on Eley (we all know it shoots exceptionally well), it just doesn't allow measurement in this way without some bracketing. Just wanted to share what I was doing for Eley on the rare occasion I do a barrel for it. BTW.....Lapua in the same chamber engraves to a "stickout" depth of .1170 (Lapua's driving band position is shorter / smaller than that of EPS, about .0190).

I have tried a million chamber finishing methods - mandrels, lapping compounds, you name it. In the end (and please, this is only my opinion) I just couldn't justify putting anything even mildly abrasive in a chamber I have tried so hard through the machining process to be dimensionally perfect and concentric. So I have concentrated on speeds / feeds and lubrication to try to machine the most clean / smooth and burr free chambers I can - and let the round count do the rest. If you are interested, I use JGS carbide reamers, at 180rpm, fed exceptionally slow (cleaning chips every .100, and .030 on the last pass) with the older (non EPA compliant) tap magic fluid. Not sure what is in that stuff, but it cuts exceptionally clean chambers with sharp tools. I chamber in a steady rest from the tailstock. There are a million ways to do it, and again, not saying this is the best way (it's just the best way I've found, for my equipment).

I hope I answered your questions, thanks for the reply,

kev

Kevin,

Thanks again for sharing this information. I'm sure it has been eye opening for many people reading it here.

These forums are to expand and improve our sport and your post has helped that.

I have read you plan to retire soon. Congratulations! Be careful or you will be busier retired than you were when you worked full-time.

Even better news was you plan to offer gunsmithing services to the general public.

I believe in the adage if you build it, they will come. Your services will allow more shooters to enjoy our sport.

I would be less than honest if I allowed readers to think I agreed with your chambering techniques for RFBR rifles.

That is not to say you are wrong. It only says my experience has been considerably different from yours.

I will not pick your post apart or try to convince you there are better ways. That would be tacky.

Thanks again for your post. I hope you make many more sharing your experience. Differing points of view can only benefit us all.

TKH

[Jerry H]

Traditional BR chambers with .100 or more engraving length are usually cleaned after each target. Position shooter typically clean at greater round count intervals. I suspect the lighter engraving is more suitable for extended cleaning intervals. Probably related to carbon ring build up rate.

[kevinnevius]

Kevin,

Thanks again for sharing this information. I'm sure it has been eye opening for many people reading it here.

These forums are to expand and improve our sport and your post has helped that.

I have read you plan to retire soon. Congratulations! Be careful or you will be busier retired than you were when you worked full-time.

Even better news was you plan to offer gunsmithing services to the general public.

I believe in the adage if you build it, they will come. Your services will allow more shooters to enjoy our sport.

I would be less than honest if I allowed readers to think I agreed with your chambering techniques for RFBR rifles.

That is not to say you are wrong. It only says my experience has been considerably different from yours.

I will not pick your post apart or try to convince you there are better ways. That would be tacky.

Thanks again for your post. I hope you make many more sharing your experience. Differing points of view can only benefit us all.

TKH

Tony:

I understand, and would never propose I am doing it correctly (just the best way I have found).

I am very interested in what you do, please let me know - I really want to learn, and your techniques would really help me do so (disagree or not).

Please contribute, that's what this forum (and all forums) should be about.

kev