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11-degree forcing cones?


Fishbreath
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8 hours ago, Fishbreath said:

 

I went ahead and measured headspace and B/C gap. Both measurements are at 0.009"-0.010" all the way around, which is right in the middle of the Ruger factory spec for headspace, and not quite in the optimal range for B/C gap but below what Ruger calls the maximum acceptable. Now that I'm pretty nearly done with matches for the year, a trip back to Ruger stings a lot less than it would've during the summer, so depending on my results from load changes and perhaps forcing cone cutting (also recommended by Ruger DA expert Iowegan at rugerforum.net, for lead bullets), it may be going on the field trip.

 

 

0.009-0.010 B/C   Did not know what Ruger's allowable tolerences were.  S&W spec is 0.004 with tolerence + 0.006 so yours is at the top of the tolerence but technically within for Smith as well.  With that said a generous gap is certainly not helping your leading issues.  Sucks it's so much work to adjust it.

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14 hours ago, tim_w said:

 

 

0.009-0.010 B/C   Did not know what Ruger's allowable tolerences were.  S&W spec is 0.004 with tolerence + 0.006 so yours is at the top of the tolerence but technically within for Smith as well.  With that said a generous gap is certainly not helping your leading issues.  Sucks it's so much work to adjust it.

 

this will contribute to a filthy gun in general and leading on the frame, yolk, etc etc..

a .010 is also costing you at least 30 fps(based on my experience of 2 guns with BC gap of .004 and a .010)...

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41 minutes ago, testosterone said:

this will contribute to a filthy gun in general and leading on the frame, yolk, etc etc..

a .010 is also costing you at least 30 fps(based on my experience of 2 guns with BC gap of .004 and a .010)...

 

Curious. It takes a lighter charge of Clays to get over the minor line than a lot of the loads I see listed here. (It'll just average 125PF on 2.6gr of Clay Dot under a 160gr bullet, but I usually load 2.8gr for the buffer, and because it burns better.)

 

I can't seem to find the photos I took at the time, but the barrel was mistimed from the factory, and I think it was mistimed in the overtightened direction—i.e., reducing the B/C gap. Solving that problem opened it up a bit, I suspect. Anyway, I don't get any spitting, at least.

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1 hour ago, Fishbreath said:

 

Curious. It takes a lighter charge of Clays to get over the minor line than a lot of the loads I see listed here. (It'll just average 125PF on 2.6gr of Clay Dot under a 160gr bullet, but I usually load 2.8gr for the buffer, and because it burns better.)

 

I can't seem to find the photos I took at the time, but the barrel was mistimed from the factory, and I think it was mistimed in the overtightened direction—i.e., reducing the B/C gap. Solving that problem opened it up a bit, I suspect. Anyway, I don't get any spitting, at least.

fair enough.

 

2.6 with a 160 bayou/ibeji was the meta load when 929's came out, a bunch of us ran that for a long while.   2.6 is borderline clays drop on a dillon bar, you need the xsmall bar to be sure you get a 2.6 everytime, or at least, that was my experience on a 1050.   I usually did a 2.4 but was only shooting in icore.   the 160's fly straighter in a 929 barrel around 775 fps, my personal theory here based on studying what bullseye guys do is the 160 is getting overspun when you go over 800, slowing it down keeps the groups better at 50 yards which used to matter alot when 'far and near' was in the IRC.   50 yard groups pretty irrelevant in uspsa except for the odd standards course or are match where an old timer wants to see of anyone can actually shoot a group or not...

 

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Yeah, I started with the extra-small bar—I wasn't sure quite where the line was with Clay Dot, but didn't want to be right on it given the

 

Interesting on the 160s and over-spinning. From what I can find, the Super GP has a slower twist rate than the 929 (1:16 to 1:10), but I'll keep an eye on how the 147s shoot comparatively.

 

Of course, upon inspection, I find that they have no less of a bevel base than the SNS Casting bullets do. Only difference is that the SNS bullets have a lube groove, which, in the absence of lube, might be meaningful?

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4 hours ago, Fishbreath said:

Yeah, I started with the extra-small bar—I wasn't sure quite where the line was with Clay Dot, but didn't want to be right on it given the

 

Interesting on the 160s and over-spinning. From what I can find, the Super GP has a slower twist rate than the 929 (1:16 to 1:10), but I'll keep an eye on how the 147s shoot comparatively.

 

Of course, upon inspection, I find that they have no less of a bevel base than the SNS Casting bullets do. Only difference is that the SNS bullets have a lube groove, which, in the absence of lube, might be meaningful?

No idea if it matters in a practical way or not, from reading old posts on here by leatham and talking to bianchi guys, more bearing surface the better seems to be the rule when trying to group super tight which makes sense.   Whether that groove matters or not?  Seems like if gas is getting past the tail and into that groove its probably not helping?  

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3 hours ago, testosterone said:

Seems like if gas is getting past the tail and into that groove its probably not helping?  

 

Yeah, that's about where I am. My Bang and Clang bullets ought to be here in a day or two, so I'm going to load 50 or so of those and 50 with the Blue Bullets, and compare them to 50 of my SNS loads in terms of fouling and dirtiness (I'll take my cleaning kit to the range and try to get things to the same starting state). I did end up renting the forcing cone reamers, but am planning on doing the initial testing before I cut on the gun at all.

 

Shape is one thing, but it's also worth noting that the Bang and Clang bullets have a Brinell hardness of 12, while the SNS and Blues fall into the 15-18 range. For mouse-fart loads like 160gr minor, a softer bullet may be a substantial improvement.

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1 hour ago, Fishbreath said:

, a softer bullet may be a substantial

Every coated bullet i ever shot in my guns resulted in leading it seems.   Only berrys plated shot totally clean but I moved off them for cost and availability.  They are objectively cleaner and shoot better groups in my experience but cost did become a factor, at some point they made a price increase that put them on par with actual jacketed bullets, which if money were no object i would def shoot...

 

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BNH of 12 is usually good to 1000+FPS with good lube and should be higher with the new coatings. The lube groove won’t make much if any difference. Hell, I’ve shot thousands of the old Speer swaged SWC’s and had hardly any leading with them. With the coated bullets there shouldn’t be nothing but maybe some plastic residue. 

Edited by Farmer
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10 hours ago, testosterone said:

 Only berrys plated shot totally clean but I moved off them for cost and availability.

 

X-Treme plated worked well in my gun (clean and accurate), but they don't make a .358 round nose, so they aren't good for fast reloading.

 

5 hours ago, Farmer said:

BNH of 12 is usually good to 1000+FPS with good lube and should be higher with the new coatings.

 

Yup, I'm well below the threshold for any of them. I'm wondering if (or hoping that) I'm not driving the SNS bullets hard enough to get them to seal, maybe.

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7 hours ago, Farmer said:

 maybe some plastic residue. 

maybe we are talking about bore vs everywhere else.   I actually get leading(or something) in the barrel with coated bullets in every revolver I shoot them through eventually, I used to shoot a lot though.   They all do pic attached pretty quickly.

 

 

leadinsmol.jpg.de93617aadbbf05c23235a7a0e6c3a2e.jpg

Edited by testosterone
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2 hours ago, testosterone said:

maybe we are talking about bore vs everywhere else.   I actually get leading(or something) in the barrel with coated bullets in every revolver I shoot them through eventually, I used to shoot a lot though.   They all do pic attached pretty quickly.

 

 

leadinsmol.jpg.de93617aadbbf05c23235a7a0e6c3a2e.jpg

A guy just needs to capture a few fired bullets and see what’s going on. Have you tried to pick those deposits off to see what they’re made up of? 

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4 hours ago, Fishbreath said:

 

X-Treme plated worked well in my gun (clean and accurate), but they don't make a .358 round nose, so they aren't good for fast reloading.

 

 

Yup, I'm well below the threshold for any of them. I'm wondering if (or hoping that) I'm not driving the SNS bullets hard enough to get them to seal, maybe.

When I was trying to come up with a good blend for my 45 I noticed that if I ran them up past 15 they would streak a bit in the bore unless I ran them hotter. Nothing bad just a little lead foil when you brushed. At 12 they ran cleaner at pretty much all the velocities. Now I’m talking a lubed bullet in an auto not coated. Revolvers have a bit more problem with the jump and gap. It still never makes any sense that a larger than bore slug will leak by but they do if they hit the rifling too fast and strip without enough psi to swell the base to fit.  

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37 minutes ago, testosterone said:

It is very hard to chip off, but it will eventually,  it appears to be lead and I think melted/burned coating and carbon.

 

I get similar patches in my chamber throats if I'm not diligent about cleaning. I got a Lewis Lead Remover that does a good job of scraping out the functional bits, and a soak in Kroil plus some tapping with a brass punch and hammer chipped off a lot of the buildup I had on the frame around the forcing cone.

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Some interesting findings already! Dr. Phil graciously sent me some test bullets of various kinds. My SNS .358" bullets will slip through the chamber throat without any extra push from me, if dropped from the back of the cylinder. Phil's various .358s fall, stick, and take some pushing with a rod to make them slide through the chamber throat.

 

Also, it looks like Blue Bullets may have changed molds recently: Phil's 147gr .358s from a year or two have a rounder nose and very little bevel, while the ones from my sample pack from early this year have a conical nose and quite a lot of bevel on the base. I'll be curious how those two in particular match up to one another, since they're nearly identical but for the bevel.

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I have some test ammo loaded up for tomorrow's range trip. Unfortunately, a little shipping mixup meant I got .356" Bang and Clang bullets instead of .358", so those will have to see some testing at a later date.

 

PXL_20211015_213928660.thumb.jpg.371356beb4f651d3690c7c0dc92012a9.jpg

 

Here are the first three bullets: the Dr. Phil special on the left, SNS casting in the middle (note similar profile but beveled base), and Rainier on the right.

 

PXL_20211015_204438085.thumb.jpg.b495200f00a0b9351e34f1d43b537710.jpg

 

There are also two flavors of Blue Bullet: a recent 147gr order on the left (note beveled base and more conical profile), and an older one on the right.

 

I tried the cylinder-drop test, too:

 

PXL_20211015_204303307.thumb.jpg.2ddc633b47d39d8f2e240392ffbf5da2.jpg

 

Counterclockwise from far left: Rainier, old Blue, Dr. Phil, new Blue, SNS.

 

The test plan goes like this, for each bullet:

 

1. Take photos of the cylinder face and the frame around the forcing cone.

2. Shoot 40 rounds, taking video of rounds 16-24 to evaluate for smokiness.

3. Wipe down the cylinder face with a dry patch to remove any loose soot.

4. Take photos of the cylinder face and frame around the forcing cone to evaluate fouling.

5. Scrub the cylinder face, frame, and chamber throats with a brass brush and CLP to tidy up, and move on to the next bullet.

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Normally, flat base bullets shoot better groups than bevel base bullets. However, there are many variables, so you can't accurately make blanket assumptions. The target downrange is always the final judge as to what works and what doesn't, for gun and ammo both.

Edited by Toolguy
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