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Post by jle300 on Feb 11, 2017 21:28:59 GMT -5
Has anyone had any trouble stabilizing a 300 grain Parker match hunter with 65 grains of IMR 4198 in a 1 in 20 twist barrel? Accuracy is excellent when the bullet stabilizes but occasionally it won't even hit the paper. Have one keyhole bullet in the paper. The other shots went into a nice group or missed the paper.
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Post by hillbill on Feb 11, 2017 21:45:36 GMT -5
I have never had that problem but I have always shot a little hotter charge, my guess is the unstabilized bullets are not engraving, you might try a wad? give us more info on loading pressure, wad or no and set up.
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Post by Kyle on Feb 11, 2017 21:45:45 GMT -5
A large part of Bullet Stability is RPM. I would advise that you measure that bullet's length and chronograph that load out of your gun. JBM has a stability calculator on their website that you can plug your data into to make an interpretation of stability. If your bullet is interpreted as being stable by the formula and you still have keyholes then you might not be getting enough obturation into the rifling with that particular combination.
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Post by jle300 on Feb 11, 2017 22:10:01 GMT -5
Thanks for the help. This is a brand new barrel. No wad and I would call it firm seating pressure. I did change the bullet sizing a couple times but that doesn't seem to be the issue.
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Post by deadeye on Feb 11, 2017 23:38:47 GMT -5
excellent advice from hillbill & kyle......... I will add it is my belief that some barrels that are slightly choked at muzzle might indeed need the wad wool or veggie.
also as mentioned your load is light & parkers jackets are a little thicker than some bullets such as the pittman accumax.
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Post by Richard on Feb 12, 2017 15:02:47 GMT -5
Another route..............
Take out 10 grains of that 4198 and put 10 gr. of N-110 under the now...........55 gr. 4198 and see if that helps! The N-110 will build some quick pressure to get the bullet obturated and engaging the rifling. This is a very conservative duplex. And if you are new to duplexing?...............there is absolutely nothing to worry about like.........if you put them in backwards or mix them? as it will only serve to dilute the results...........NOT increase anything!
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Post by jle300 on Feb 13, 2017 19:44:41 GMT -5
Also, has anyone done any testing with the 300 grain match hunter that has the cupped base? Seems like that might fix the problem.
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Post by jle300 on Feb 13, 2017 19:44:57 GMT -5
Also, has anyone done any testing with the 300 grain match hunter that has the cupped base? Seems like that might fix the problem.
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Post by doug136 on Feb 15, 2017 20:31:32 GMT -5
I have some and have shot them . I'm not impressed . I didn't think the shot any better and they are a pain to size . Just my opinion
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Post by Deleted on Feb 15, 2017 20:39:36 GMT -5
Not match hunters but WGK and I were at the range a couple days ago conducting a chronograph shootout while simultaneously testing H322 with 300 SST's in his 1:18 brux with charges from 79 to 83gr. We began noticing key-holes on the target and found that a wad was needed to stabilize them. While his gun always shoots good without a wad, for some reason this powder bullet combo required one.
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Post by 865mlkill on Feb 15, 2017 20:54:38 GMT -5
I have previously shot the 300 MH's with 65 grains of imr 4198 with a 1:22 twist barrel with great results (no keyholes) with good accuracy. I don't know why you have had a keyhole to happen. For stability, I took a doe at 608 yards with this set up with no problems
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Post by Richard on Feb 15, 2017 21:22:38 GMT -5
I think what we are dealing with is the fact that every barrel can be slightly different in dimensions and require slightly different sizing. Bushing size and delivery systems can vary and if you are on the ragged edge, you might experience a stability problem. One trip to the range Herman was raving about how good his 250 SST's were shooting and the next time he had a stability problem??? Go figure? The trick is to have all your components consistent. I have found with the 300 gr. XTP if I under size by about .0004", then run the file over them a few times and then run them thru Hank's smooth die at a particular setting that EVERY bullet has the same feel going down the bore and accuracy is great. I have other bullets that I just run once thru a particular die and they are good to go........Kyle's in particular!
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