RF reamer for sk ammo
- Thread starter chris l
- Start date
tonykharper
Well-known member
Chris,
Your question is a little vague to give you a good answer.
There is nothing unique about SK .22LR ammo that would require a special reamer.
Any reamer on the chart would work. However, the action you use may work better with particular reamers.
example: A bolt action can use tight short chambers with full bullet engraving, but an auto will have problems with that type of chamber.
TKH
Hi-NV Shooter
Member
There are different thoughts on what is ideal. here is one that I been using for several years with great results. go to Rimfire Accuracy and look up this thread by Kevin Nevius Team Lapua shooter
https://www.rimfireaccuracy.com/Forum/index.php?threads/testing-chambers-for-lapua-use.23372/
Lee
tonykharper
Well-known member
Chris,
Could you describe the differences in a Lapua chamber vs an SK chamber.
The Nevius chamber you refer to I believe has a 1.5-degree lead and the depth is set for minimal bullet engraving.
I don't recall if it is a straight sided reamer or tapered.
You may know the late Bill Meyers used a chamber of this same description for shooting ELEY ammo with great success.
What exactly would one do different for a PRS rifle using SK ammo?
Not trying to put you on the spot or steal secrets but would like to learn what is the current thinking?
TKH
Hi-NV Shooter
Member
Hi-NV Shooter
Member
Tony, I believe the rifles are magazine fed so maybe tradition BR chambers may cause an issue.
Lee
tonykharper
Well-known member
Lee, as
I think you are right. Many people use fully engraved chambers for single shot Benchrest rifles.
Since most actions do not have adequate closing cam they often have to use their thumb to push the bolt forward enough to close the bolt. That would not work well for someone running cartridges through a magazine. So a deeper chamber would be helpful.
TKH
tonykharper
Well-known member
Hi-NV Shooter
Member
Hi-NV Shooter
Member
Tony, I just remembered that some of the rifles for this type of shooting have what is called control feeding. the RimX comes to mind as you can't feed single rounds it must feed from the magazine.as the round is stripped from the mag it is captured and held by the bolt so it will go straight into the chamber not sure with this feed system a BR type chamber can be used.
Lee
tonykharper
Well-known member
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
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Aware of that but here, he had the modded magazine and we shot mostly ELEY.
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Well, like you, I would tend to credit most of it to a nice barrel.
My primary point was that it fed without issue from the magazine.
Did not shoot full cards, but this was a rig in a hunter type stock and running through 15 consecutive IR 50 bulls with no sighters between I got 12 X’s and one hard 9 on a good morning.
Pretty good for what that was, shooting ammo I sold him, so not my best.
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
Well-known member
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
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kevinnevius
Member
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/Forum/index.php?threads/testing-chambers-for-lapua-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
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/Forum/index.php?threads/testing-chambers-for-lapua-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
tonykharper
Well-known member
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