Hollow pointing boolits to reduce weight to increase stability

[15meter]

As the title says, does reducing boolit weight help with stability?

I had problems with a 416 Rigby feeding with a rather blunt boolit so I had Accurate make me a mold that duplicated a factory profile bullet that feeds very well. Weight went up, being an all lead boolit. Fed like magic.

Stability went in the toilet, like flat out sideways on the target at 25-50 yards with very light loads(1200-1300 fps Trailboss load). If it even hit the 30"x30" piece of paper so we could see the perfect keyhole.

Sped the load up(1700+ with 5744), better but not great.

If you're still with me after the long winded explanation, would drilling a hole (hollow pointing) the boolit to reduce weight help with stability?

My google-fu is not particularly good today to do a search, too many cold/cough remedies in my system, so it's time to see if anybody else has an answer.

One rifle has a 16-1/2" twist second has 14". 14" twist is better but not awesome.

Would reducing the weight through hollow pointing help with stability, or should I stop trying to think?

[megasupermagnum]

That's a big open ended question. I'll just say that I have found hollow points can often increase accuracy, at least in handguns. I don't think in my case it had anything to do with stability per se, I think it moved the center of gravity back, and just made them balance better. I believe this is why the most accurate bullet designs in handguns are often either SWC, or hollow point, they are better balanced. I've yet to find a round nose of any flavor be impressive.

Is there any reason you can't load the bullets you have any faster? The load data I'm seeing shows 416 rigby should have no problem sending a 400 grain bullet 2200-2500 fps. Ouch.

[15meter]

The OUCH is why.

Looking for dinger ringer loads that I can shoot a box or two without developing a lifetime flinch. @ 1700+ it still gets your attention.

Plus trying to avoid leading, did that with a 450 Nitro Express. ONCE.

[shortlegs]

The length of the bullet determines twist rate not the weight. Also if you have leading problems boolit size or alloy or lube could have caused leading. A lighter weight cast boolit of the right alloy with good lube would be pleasant to shoot.

[Larry Gibson]

The length of the bullet determines twist rate not the weight. Also if you have leading problems boolit size or alloy or lube could have caused leading. A lighter weight cast boolit of the right alloy with good lube would be pleasant to shoot.

^^^^^^^

Yup

[BrutalAB]

To add to this, the reason hollow points can help on stability is the boolit will be moving faster, thus achieving the higher rpm that the boolit needs to stabilize.

[GregLaROCHE]

Many competition jacked rifle bullets are hollow points. This is to reduce the weight in front of the main mass of the bullet. These bullets have a much greater length to width ratio than what you’re talking about, but this same principle may still improve stability in flat nosed bullets as well.

Nonetheless, you still need an adequate charge to stabilize any bullet. Also, if you go below minimum recommend charges, lower pressures may prevent the powder from burning correctly. That can result in varying muzzle velocity, therefore accuracy.

[USSR]

Many competition jacked rifle bullets are hollow points. This is to reduce the weight in front of the main mass of the bullet.

Not really. It is a result of having a more perfect bullet base by inserting the lead core from the front of the bullet jacket instead of the rear. The bullet base is much more critical for accuracy than the bullet tip.

Don

[Larry Gibson]

15meter

What is the length of the bullet, with GC, that you are using?

[GregLaROCHE]

Not really. It is a result of having a more perfect bullet base by inserting the lead core from the front of the bullet jacket instead of the rear. The bullet base is much more critical for accuracy than the bullet tip.

Don

Sorry to disagree, but if more of the mass is consolidated at the center of the bulle, it will be more stable. Maybe some others will help me out with more details.

[bmortell]

it sounds like you have a longer projectile since you said you went from a blunt bullet that don't feed well to something more like factory rounds. but no id think hollow pointing it would just keep the same length with a more rear heavy balance and be harder to stabilize. if anything you want to hollow point the rear end so it stabilizes easy like a foster slug or minieball.

id just make sure the diameter is good and try harder lead to see if its more stable, if not rpm stability for that length is whats left, so you need more speed and rpm's. making them hollow base for shuttlecock effect should help on paper but not realistically something id want to do.

for the jacketed accuracy/balance thing I don't think that has to do with balance there just shape optimized for drag, there natural balance is backwards.

[15meter]

This was basically a duplication of a good shooting jacketed bullet in cast. I sent Accurate a jacketed bullet that feeds very well and shot great. I asked him to duplicate it in a g/c cast boolit. The mold casts a beautiful slug that weighs 384 grains.

Overall length is 1.245, I was hoping that a hollow pointing job would let me keep the speed down, reducing the OUCH factor.

[bmortell]

well technically hollow pointing the nose would reduce weight which helps recoil, but youd have to still increase the speed for the stability which increases recoil. and if its a more pointed aerodynamic shape you cant effectively remove very much weight cause the nose isn't that wide. so overall its probably not that efficient at solving your problem. normally id say just keep that mold for high power loads and get a lighter weight cheap mold for low speed loads but 42 cal isn't common so sticky situation

[country gent]

I believe you are right at the edge. With increasing the velocity making it better. When the all copper bullets first came out the standard weights for caliber shot poor due to added length. For what your wanting a bullet in the 1.1" range should be very close. What you might try with your existing bullet is to cut the first band and grease groove off. shortening the bullet probably about .100 and test.
If you have a case trimmer with collet to hold the bullet it can be done there. or with a couple pieces of hard wood clamp together drill 2 dowel holes thru sides. Then in a vise drill a bullet dia sized hole to correct depth. you want the hole size for size or a couple thousandths smaller. When you drill this hole have e pieces of index card between them to provide a small gap to allow clamoing pressure.

In use set in vise. drop bullet into hole resting on bottom. clamp with vise. With a fine blade hack saw or jeweler's saw cut bottom off and file flat to fixture. Make a group to load some test ammo. IM betting the shorter length will make them better.

A small lathe with collets and a collet stop would make this easy to do in one pass. set bullet into collet against stop. Use a cut off blade and cut to length. Lock carriage down in place or set a stop for it.

Hollow pointing will lighten the bullet but wont change the length. Cutting the nose back changes the working profile you want / need. Make a cou[le extras so if they work you can send them to the mould maker to show what you need. Or you may be able to cut the blocks down that much also

[megasupermagnum]

This was basically a duplication of a good shooting jacketed bullet in cast. I sent Accurate a jacketed bullet that feeds very well and shot great. I asked him to duplicate it in a g/c cast boolit. The mold casts a beautiful slug that weighs 384 grains.

Overall length is 1.245, I was hoping that a hollow pointing job would let me keep the speed down, reducing the OUCH factor.

I don't see the exact bullet based on that. Is there any chance it is the #42-365S ? I don't put much faith in the bullet stability calculators, but I tried three online, and all three say that should be more than stable, even with the 16.5" twist at 1200 fps.

I would think it better to start at the basics first. Bullet fit being #1. This forum is littered with people who had tumbling bullets that turned out to be undersized.

[15meter]

I don't see the exact bullet based on that. Is there any chance it is the #42-365S ? I don't put much faith in the bullet stability calculators, but I tried three online, and all three say that should be more than stable, even with the 16.5" twist at 1200 fps.

I would think it better to start at the basics first. Bullet fit being #1. This forum is littered with people who had tumbling bullets that turned out to be undersized.

That's the mold I had Accurate design, it measures 1.245" with g/c. It really is a nice boolit, and it feeds perfectly.

I have not and will not slug the bore of this rifle, it's a friend's custom rifle that cost more than my last truck.

May try pan lubing some as cast, don't remember the as cast size and don't have any that haven't been sized.

The pot is on the bench and I got the mold out yesterday, may be the new year's Eve project.

What old geezers do for excitement

[USSR]

Here's a good article regarding the differences between full metal jacket bullets and hollow point rifle bullets, and the importance of the bullet base: https://www.ssusa.org/articles/2018/...more-accurate/

Don

[Larry Gibson]

That's the mold I had Accurate design, it measures 1.245" with g/c. It really is a nice boolit, and it feeds perfectly.

I have not and will not slug the bore of this rifle, it's a friend's custom rifle that cost more than my last truck.

May try pan lubing some as cast, don't remember the as cast size and don't have any that haven't been sized.

The pot is on the bench and I got the mold out yesterday, may be the new year's Eve project.

What old geezers do for excitement

What size do the bullets drop at?

What are you sizing at?

Lube or PC?

[Bent Ramrod]

I have a .44 paper-patch mould that casting at 500+ gr was too long for the twist in my rifle. I had read that the Canadian blackpowder shooters used hollowpoint cast boolits for extra stability at long range (this in the 80s) so I drilled holes of various depths in the noses to see if they flew with less yaw. It’s written up in the BP paper patch section. IIRC, I might have had fewer oval holes in strings of 5 at the Pig and Turkey lines, but the treatment didn’t totally eliminate them.

Still have 50 of the overlong boolits; too many other projects have delayed getting back to the experiment. Drilling holes in lead is pretty tedious, too.

[swheeler]

As the title says, does reducing boolit weight help with stability?

I had problems with a 416 Rigby feeding with a rather blunt boolit so I had Accurate make me a mold that duplicated a factory profile bullet that feeds very well. Weight went up, being an all lead boolit. Fed like magic.

Stability went in the toilet, like flat out sideways on the target at 25-50 yards with very light loads(1200-1300 fps Trailboss load). If it even hit the 30"x30" piece of paper so we could see the perfect keyhole.

Sped the load up(1700+ with 5744), better but not great.

If you're still with me after the long winded explanation, would drilling a hole (hollow pointing) the boolit to reduce weight help with stability?

My google-fu is not particularly good today to do a search, too many cold/cough remedies in my system, so it's time to see if anybody else has an answer.

One rifle has a 16-1/2" twist second has 14". 14" twist is better but not awesome.

Would reducing the weight through hollow pointing help with stability, or should I stop trying to think?

Your bullets should be stable in either barrel sub sonic. Sideways at 25 yds you must be leaded up to smoothbore status