Shorty Bullets

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rodwha

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I noted this past range trip that some of my 170 grn WFN .45 cal bullets were beginning to keyhole at 15 yds.

I'm not sure if this is in part due to them being so short (.400") or if speed also had something to do with it as I was using 30 grns of 3F Triple 7 through my 5.5" Remington.

I'll be trying some more next time I cast up enough and get back out there.

I'm wondering if I were to hollow point it, making the rear much heavier, would help stabilize them better.

Here's the bullet:

http://www.accuratemolds.com/bullet_detail.php?bullet=45-170C-D.png
 
That's a somewhat uncommon design. There seems to be sufficient driving band width, though. What is the groove diameter on your piece? .456" should be getting well into the grooves on most revolvers. What's the twist rate? Older Pietta models had a very slow twist 1:30. With a shorter barrel and slow twist, you may be round ball only.

Short isn't the problem and even 30 grs T7 won't deliver much more than 850 - 900 fps, so velocity is within norms. My guess is that slow twist rate and shorter barrel length are not delivering sufficient spin to give the bullet stability at distance.

Check the twist rate. If it's a 1:18, then twist is not the issue. If it's 1:30 and the keyholing is with longer shots rather than shorter, then you have a round ball gun. If twist is not the issue, I'm stumped.
 
Or the bullet is being driven too fast and is stripping and leading. Or the heavy powder charge is blowing past the base, I'd reduce the charge and if that cured the problem amp it back up gradual until the keyholeing started again, then drop back until you find a happy medium.
 
Certainly uncommon. Love Accurate Molds!

I increased the driving band widths to increase pressure over typical bullets.

My grooves are .452" as I drove a ball recently. I didn't check the lands and melted that ball…

When I did my check for twist I came up with something like 1:18, though I've been told they are 1:16, and so I'm sure my test wasn't quite adequate. This was purchased around Christmas.

I think 30 grns of 3F T7 will give over 900 fps. I can't show it does it in mine, but I've seen plenty of testing to think so. 33 grns behind a ball gave 1062 fps in a Ruger.

I intend to use my box as a rest at the 7 yd line just to get a better idea of what's going on as far as accuracy and printing. Several didn't hit paper as they were far left and low, which I thought seemed unusual also. I thought these guns generally shot high. But that's OK as I can file the sight for these.

I doubt I'm getting much blow by, but with .446" chambers I suppose it's possible. I'm sending my cylinder off to have the chambers reamed to .449" and chamfered. The ring of lead is rather large!
 
Just a gut feel, but I think hollow pointing and putting most of the weight in the rear would make it worse.

Put some weight back near the fletching of an arrow and see what it does for accuracy. (it won't help)
 
I read somewhere that rearward weight helps bullets, which is why match grade rifle ammo uses hollow points. I don't recall where I read that, and I'm not sure if they knew what they were talking about.
 
I haven't had as much opportunity as I'd like, and I'm no pistolero, but from what I've seen so far is that the 195's shoot quite well, as well as anything else I've put through my Ruger, which spits everything out well. It's been fed .457" ball, 180 grn RNFP, 190 RN, 195 SWC, 200 SWC backwards, 230 RNFP backwards, 240 Kaido bullets, and now these 170's and 195's.

Despite my measuring beforehand I hadn't taken into account the wide nose, and so the 285's wouldn't fir into the loading window of my Ruger. As I don't have room in my box for a loading machine, not would I want to carry anything extra afield, I broke down and modified the window myself. Now they fit, and I'm looking forward to trying them out!

I had to modify my Pietta Remington to get the 170 and 195 to fit, and it's what gave me the confidence to try it on my Ruger.

My Remington is still new, and so I'm not really sure what to expect from it, but it does make me appreciate my Ruger!

Since the 170's were sometimes tumbling I'm unsure of it at this point. I need to try a smaller powder charge to see if speed plays a part. I don't recall noticing any partial key holing from my first range trip, but maybe I just didn't notice it. It wasn't terribly obvious. I also had used Olde Eynsford powder prior, and likely 30-35 grns. Triple 7 seemed to make it recoil much like a .44 Mag. It seemed much more stout.

I've asked my range about a private bay and being able to test expansion/penetration with wet phone books, and I was given the OK by the man in charge there. Cool! Now I need phone books!
 
Went back to the range yesterday with lubed bullets this time and got great results. Obviously the lack of lube caused my previous problems.

I found that my 5.5" Pietta Remington '58 loves 30 grns of 3F Triple 7 or Olde Eynsford with both my 170 and 195 grn bullets.

I tried both 25 and 35 grns, but the groups opened up with the 25 grn charges being far worse.

I also found that my Pietta shoots low and left.
 
As for bullet length, there is the Greenhill formula that matches speed and twist to ideal bullet length, but it sounds like you found the improvement necessary. IIRC correctly, short bullets need to spin faster to stabilize. OTH, could be the lube is enough to prevent blowby. Or even that barrel fouling led to the keyholing.

Match bullets are not hollow pointed, at least not in rifles. There were some very purposely designed pistol bullets developed around 1900 for match shooting that had very square shoulders and slightly raised point in the center. I have a mold for these that fits my Ruger OA and they do well in the ruger. It is an old Ideal mold for the 455 Webly and 455 Bulldog. It throws a 192 grain pure lead .456 bullet.
 
Shorter bullets work well with slower twists, right? I first noticed this when the AR's were trying to shooting longer bullets and were in need of a faster twist.

I contacted a fellow who has a web site devoted to figuring twist rates, and this 170 grn .400" long bullet was not inside the ideal length for the 1:16" twist the Ruger barrel (and the Pietta come to find out) has. I sent him an email and my response was that it was "over" stabilized. He felt it ought to work, which is why I went ahead and had a mold cavity designated for it.

I had found a little sliver of lead while cleaning my Ruger, and so I am assuming leading may have been a problem in the Pietta as well, and may have been the source of my problem. But that's speculation as I have no good idea, though speed didn't have any bearing on it as they all flew straight on Monday.

I had figured my accurate load would likely be similar to that of what many claim when shooting a RB, that it would be below 25 grns. I'm wondering if this is barrel harmonics or something else.
 
You cannot "over stabilize" a bullet. In theory one can push rpm to the point where, based on bullet construction, it can spin apart. You run no such risk at 1000 fps with the 1:16 twist. In fact, 1:16 will stabilize anything you can fit in your cylinder with enough powder to get it out of the barrel.

You can adjust your Pietta sites to correct for 2" low and Left with a set of diamond grit files. First, shoot it a few more times with the loads you intend to use. Make sure there I'd consistency with the low and Left. If so, first file down your front sight gradually until you bring POI up to where you want it. Then, very gradually, open up the right side of the rear u channel sight. This will force you to move the rear of the gun slightly left to center the front sight. Very gradually correct to desired POI.
 
short bullet faster twist vs long bullet slower twist. at least at subsonic speeds.

and by faster and slower, it means in the neighborhood of twists between 1:8 or 1:12 to slower 1:18 or 1:24.
 
Zimmer,

You seem to have this backasswards. A tighter twist is required to stabilize a longer projectile vs that required for a shorter projectile.

Rodwha,

It won't take much to move your POI to center. Just be very deliberate and gradual.
 
I'm wanting to get as close to POA at 15 yds, and I was noticing this difference at a mere 7 yds as the last time they were faaaaar left they often missed paper so I moved closer so as to get a better idea of what was going on. I see they are still left, but at least not too far.

I'm thinking of putting an inclines pitch to my sight similar to a more modern form. It seems it would be less likely to snag this way.
 
"I'm wanting to get as close to POA at 15 yds, and I was noticing this difference at a mere 7 yds as the last time they were faaaaar left they often missed paper so I moved closer so as to get a better idea of what was going on. I see they are still left, but at least not too far."


In all honesty, if you can not hit the paper at 7 yards, there are one of 2 problems, the pistol has major problems or it is you.
 
Many of my bullets were missing paper while at my normal 15 yds range. They were beginning to tumble from lack of lube in the grooves it seems as I moved up to the 7 yd range this last time and they were 1-2" low and 1" left.

I typically can keep a 3" or so group at 15 yds offhand.

I can't get them all to touch, but I can easily keep them all center mass at 15 yds offhand.

I can do a bit better with my Ruger.
 
rodwha said:
Certainly uncommon. Love Accurate Molds!

I increased the driving band widths to increase pressure over typical bullets.

My grooves are .452" as I drove a ball recently. I didn't check the lands and melted that ball…

When I did my check for twist I came up with something like 1:18, though I've been told they are 1:16, and so I'm sure my test wasn't quite adequate. This was purchased around Christmas.

I think 30 grns of 3F T7 will give over 900 fps. I can't show it does it in mine, but I've seen plenty of testing to think so. 33 grns behind a ball gave 1062 fps in a Ruger.

I intend to use my box as a rest at the 7 yd line just to get a better idea of what's going on as far as accuracy and printing. Several didn't hit paper as they were far left and low, which I thought seemed unusual also. I thought these guns generally shot high. But that's OK as I can file the sight for these.

I doubt I'm getting much blow by, but with .446" chambers I suppose it's possible. I'm sending my cylinder off to have the chambers reamed to .449" and chamfered. The ring of lead is rather large!
Click to expand...
Most conicals will shoot high in my Pietta Remmy .44
 
That's what I've typically read. So I'm surprised and happy that mine doesn't.
 
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