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Post by mountainam on May 23, 2011 7:52:23 GMT -5
I was browsing the McGowen barrel site and contemplating a sabotless barrel on a 700ML action. I would like to know how much larger or smaller than the bore size bullet I would need. I am looking at a few options. Shooting .366" bullets in a .375" barrel; using .358" bullets in a .366" barrel or using .348" bullet in their .358" barrel? I also see they offer micro-grooved barrels in .358" caliber. I don't know if it's a typo or not ,but they show the micro-groove barrels as having the same depth as the standard rifling. I was under the impression that Micro-groove rifling was shallow compared to standard or Ballard type and that the shallow rifling may be more suitable to sabotless use. I need some design and theory info from the sabotless Guru's. Thanks!
Ambrose
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Post by fishhawk on May 23, 2011 12:03:22 GMT -5
If I was doing a sabotless only with no state caliber restrictions I would use the barrel that the groove diameter matched the bullet diameter. With a requested barrel drop you might check with Swinglock about getting a fullform die made. If he would do these smaller sizes you could use, .358 bullets in a .358/350 barrel. Or .366 bullets in a .366/.358, or .375 bullets ina .375/.368.
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Post by mountainam on May 23, 2011 13:47:35 GMT -5
I guess that's where I see the inconsistencies cropping up. I see some fellows using bullets at 1 or 2 thousanths under the BORE size with a fiber or felt wad and still get very good accuracy. I hunted in Ohio with a ML for going on 36 seasons now and have yet to have my caliber checked. We have a .38 cal minimum so a .375 should satisfy that if we round the number off to 2 digits, unless that number rounding rule I learned in 4th grade doesn't apply to Governmental math anymore.
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Post by Jon on May 23, 2011 14:50:52 GMT -5
I had a 6.5 die made by Swing Lock that I am very happy with. If you are talking about Gov. round off that is a different thing it is going to be what is good for them. That is why I'm looking at a .392 .400 for my next build. I defiantly want to go full form.
Jon
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Post by fishhawk on May 23, 2011 16:22:13 GMT -5
I guess that's where I see the inconsistencies cropping up. I see some fellows using bullets at 1 or 2 thousanths under the BORE size with a fiber or felt wad and still get very good accuracy. I hunted in Ohio with a ML for going on 36 seasons now and have yet to have my caliber checked. We have a .38 cal minimum so a .375 should satisfy that if we round the number off to 2 digits, unless that number rounding rule I learned in 4th grade doesn't apply to Governmental math anymore. Are you talking 1or2 thou under the land or groove diameter. There is sabotless with bullets that are just under the land diameter either sized or not then knurled up to tighten them in the bore. Now there is the fullform die that engraves rifling in bullets that are over the land diameter. |
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Post by mountainam on May 23, 2011 17:16:45 GMT -5
fishhawk, Yes I was referring to the lands. On McGowen's site they refer to it as the bore and groove diameters. I see some fellows using what seems to be bullets under the land to land diameter still get some tight groups. I would think obturation would not be a factor with full form dies.
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lc
Forkhorn
Posts: 72
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Post by lc on May 23, 2011 17:49:18 GMT -5
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Post by fishhawk on May 23, 2011 17:53:15 GMT -5
Most that are not using fullform dies are sizing bullet that started over the land to land diameter to less than .001 under the land to land diameter, then knurling up for a tight fit. some are then taking those knurled bullets and resizing with a smooth or fullform die to get the knurl closer to the diameter needed for a good fit.
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Post by deadon on May 23, 2011 18:26:46 GMT -5
fishhawk, Yes I was referring to the lands. On McGowen's site they refer to it as the bore and groove diameters. I see some fellows using what seems to be bullets under the land to land diameter still get some tight groups. I would think obturation would not be a factor with full form dies. Mountain, pm DougEdwards, He has an rb special in a weird caliber or size, It is a 45 cal but something is different about the actual size. He tested bullets for years trying to find a bullet sabot combo that worked. Finally one day we were shooting and he had sized some bullets to try sabotless. He had tried some that he had to literally hammer down the barrel. These went down the barrel so easy he was afraid they might fall out. Well BINGO, IIRC almost touching groups at 100 yrds, Maybe he will jump in here if he ever puts down his new Bow, Smiling , Rusty |
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Post by Dave W on May 23, 2011 20:12:43 GMT -5
If it were me- I would opt for a full form die if it will work with boattail bullets to take advantage of the higher BC bullets. I think Jims has a .375.
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Post by jims on May 23, 2011 21:11:08 GMT -5
I have a .375 Krieger, the lands are .366. I feel I have a bit of a taper in the barrel, tighter at the muzzle than the breech and that has caused me some problems in a muzzleloader. In absolute fairness to Krieger they did not know I was going to use it as a muzzleloader. The way it was configured would work well with a centerfire. The taper I think is only about .0002, it was not checked with a pin gauge.
Krieger was great about it. They agreed to re-lap it to a uniform bore size, no taper, from breech to muzzle. It was sent out today. I only had to pay return shipping. One could not ask for more than that. The problem was all mine as I did not specify this no taper originally.
I am not sure about the turn around time but at least they were willing to work with me so I appauld them for that, they did not have to do anything but volunteered to do this so I cannot ask for more out of a company.
The easiest procedure was to knurl undersize .365 bullets up to size or use the swingloc to reduce .366s (9.3mm) down a bit. The trick to get the exact size, especially with the taper, was the problem Generally sizing under and knurling up seems to be the way that appears to be the solution.
That is what I do with RBs .40 PacNor. The bullet is undersize, 200 ssts and then knurled up. They fit loosely but shoot well. I hope the same works for the .375. The "advantage" as I have said before if it really is one is the 9,3mm bullets are true centerfire bullets and I am hopeful that will provide some benefit. Deadeye provided great help to me on trying to wring out the .375 but the taper was something that needed to be addressed before anything meaningful more could be done. Edge reviewed possible powder ideas. SW and others gave encouragement. I am sure I missed others that gave help/ideas and apologize for those missed.
I hope this helps a bit.
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Post by dougedwards on May 24, 2011 22:15:34 GMT -5
I only see one option if a shooter decides to shoot a muzzleloader with modern bullets and no sabots and that is to employ the Swinglock full form die to size bullets. This die is so micro adjustable and allows you to play with the sizing of the bullets until you reach a fit that provides good accuracy.
I bought my Pac Nor from Rick Bibby who mistakenly ordered the barrel with a .451 land to land measurement as a pistol barrel would come. There is no bullet/sabot combination that I know of that will accommodate this size tube. Every bullet must be sized down to shoot the bullets without sabots which means .451 or .452 diameter bullets. My problem was with "spring back". Out of a batch of bullets that were sized down enough to fit snuggly down the barrel several of them would bulge back out over time. One bullet in the batch would push down the barrel firmly when the next bullet had to be hammered down (which is not good).
I decided to reduce the size of the bullets to the point that they could be pushed down with just my thumb and index finger making contact with the push rod. To my surprise these heavily compressed, thickly laden copper coated bullets obturated extremely well when slapped in the rear with higher pressure loads such as a 20/45 ratio of N110 over Alliant 10x. The evidence was uniform muzzle velocity and almost hole touching accuracy. This was with the Savage 10ML2 bolt action.
I have sent my barrel and bolt action off to get painted and am hoping to get them back soon to do some more testing. In any event, my suggestion is to send Tom Post your barrel so that he can make it one inch shorter and create a "must have" compression tool for sizing bullets to an exact specification. Tom,of course, will professionally recrown the barrel and send it back to you with the full form sizing die. It seems the only way to go if you choose to opt for sabotless only shooting.
PS......I am also thinking of converting a Rem 700 action muzzleloader to smokeless. As soon as I find the time and the courage I am going to do it.
Doug
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