Why JHPs

[Nemesis Lead]

Many guys at my club reload for 40 major using JHPs.

Is there a reason for this? They seem more expensive, less feed reliable (although this is certainly not always the case), and longer for the same weight bullet.

Can someone enlighten me? I may be missing something and want to know what it is!

[lee blackman]

Accuracy

[bikerburgess]

JHP equals no exposed lead on base of bullet so the gun will run cleaner. also many guns shoot JHP more accurately than they do with other bullets.

Mike

[twodownzero]

They don't have any exposed lead at the base, and so they're a good way to eliminate fouling and smoke.

Some people find that they are more accurate.

[gng4life]

The process they use to produce those bullets helps with the flight path, I get better accuracy out of them in all my guns. Some only very slightly but enough to notice.

[racerba]

...longer for the same weight bullet.

IMHO...

Longer is the key to more accuracy. The longer the bullet, the more lands and grooves the bullet has in contact with the barrel producing a more consistent flight path = more accuracy.

[co-exprs]

The answer is molecules. With a round nose or flat nose bullet the air molecules are forced by the bullet profile to move around the nose. Manufacturing imperfections cause the airflow to be flawed. With a hollow point, the air molecules stack up in the void and form thier own profile which is perfectly balanced on the rotating axis. This creates a self centering nose on the projectile.

[UW Mitch]

I thought it was because I ordered a case of the wrong bullet and didn't feel like paying return shipping to get FMJ's They also make nicer holes in cardboard. But I think the guys already covered the legitimate reasons for using a JHP.

~Mitch

[Nemesis Lead]

Great answers guys! I had no idea.....

[jmbaccolyte]

A gunsmith (who is also master level shooter) told me jacketed bullets are more accurate because the bullet diameter is matched more accurately (with modern manufacturing techniques) to the bore diameter.

Edited July 9, 2012 by jmbaccolyte

[jmbaccolyte]

The answer is molecules. With a round nose or flat nose bullet the air molecules are forced by the bullet profile to move around the nose. Manufacturing imperfections cause the airflow to be flawed. With a hollow point, the air molecules stack up in the void and form thier own profile which is perfectly balanced on the rotating axis. This creates a self centering nose on the projectile.

I have never read of any experiments being conducted on this subject, but would assume that this would apply more to rifle distances than common pistol distances (25 yards or meters).

[Warhammer4k]

Complete metal jacket (CMJ) bullets, such as those sold by Montana Gold, also have no exposed lead, but are cheaper than JHPs. I'm nowhere near a good enough shot to tell the supposed difference in accuracy at 25 yards or less, so I shoot Montana Gold CMJs. I bought the CMJ version because it was only a fraction of a cent more per bullet, so I figured it couldn't hurt to have less vaporized lead floating around. The tiny amount of lead from the base of an ordinary FMJ bullet isn't going to lead up your barrel anytime soon, but why have it in the air, and on your hands & clothing, if you don't have to?

I'd love to be proven wrong, but for me the "accuracy" justification for JHPs just doesn't make sense, for a variety of reasons.

[Mbauer67]

Because they look cool and shot a little better groups

[Poppa Bear]

Hollow points by design are lighter at the nose than at the base so they have a more stable spiral as they fly down range. This makes them just a bit more accurate.

[fiddler]

I fly model gliders, another obsessive and expensive hobby. Getting the Center of Gravity (C/G) of your model at the sweet spot makes all the difference between having a model that flies and having a model that flies great, is responsive and goes where you point it. Sometimes it's just moving the C/G a half inch in a model with a 100 inch wingspan. I imagine bullets share some of these characteristics and hollow point bullets have to have a C/G that is a little further back than solid bullets. That's what I figure.

Edited July 10, 2012 by fiddler

[Jeff686]

...longer for the same weight bullet.

IMHO...

Longer is the key to more accuracy. The longer the bullet, the more lands and grooves the bullet has in contact with the barrel producing a more consistent flight path = more accuracy.

Are you implying that shorter bullets will jump the lands/grooves? If not, how exactly does a longer bullet interact with the rifiling in a more accurate manner? It can't spin faster. Does it exit the barrel crown better? Is it less damaging to the jacket during initial rotational acceleration? I seem to recall that some barrels are designed with variable twist grooves to slowly apply rotation, but I thought that was for long guns.

Help me understand.

[gm iprod]

All the above and some.

One theory I heard years ago was, longer bullets tend to shoot better because the longer bearing surface has less chance of letting gasses last, I can't prove or disprove or that, but when I was starting out they had way betetr scores than I did.

All the Bullseye guys I know will shoot a Hollow Base Wadcutter or Hollow Point over a full wadcutter any day. All the testing that I have done in twenty years of pistol shooting (12years shooting NRA AP internationally) I have plenty of data to show that the 38Super, 9mm, 38Special, 45ACP, 44MAgnum and 40S&W all show a prefference for the longer bearing surface. Not neccessarily heavier bullets but within a bullet weight group the longer the bullet the better it shoots, at any range. I will take any advantage (however insignificant it may appear) to the line with me. I have enough troubles without worrying about whether or not this thing will shoot 1.5" at 50, not 4".

JHP are manufactured from the back forward and the rear part of the bullet is protected within teh manufacturing die and is more likely to be better made that the front which is pressed into the shape buy a punch and can deform during the manufacturing process. As the bullet leaves teh barrel the more perfectly shaped back of the bullet is the last part to have contact with the barrel. Any deformation of the base will cause poor accuracy. So with a bullet made back forwards the bullet will leave the barrel more accruately. Anything made front to back will have tiny impoerfections that touch the barrel last and will cause miniscule deviations that get progressively worse teh furtehr fromt eh barrel contacts a target.

Exposed lead bullets leave large amounts of residue in compensators. That lead came from somewhere. Some of it will surely be left in the barrel at the same time, any extra residue in a barrel will degrade accuracy. Again any way I can reduce by even the miniscule amounts of lead per shot over 500 rounds I will take. It gets progressively worse as the residue increases. The more there is the more that gets left behind. Top 35 finishers at Bianchi Cup used JHP as far as I can gather the info.

[noylj]

GM irpod wrote: "Exposed lead bullets leave large amounts of residue in compensators."

I always shake my head at this. I have been shooting lead in various compensated guns (.38 Super, 9x21, .45 Auto) for over 20 years and NEVER cleaned any lead from my compensators.

I have one I bought used that has a very rough base in the compensator, but I have never scrapped any lead from it and it seems to be simply rough machining of the steel. Even picking at it with a steel dental pick only removes the black powder residue.

I always thought the key to the accuracy of HBWC, SWC, and HPs was the slightly longer bearing surface. I have tried Zero 185gn swaged SWCHPs, that have the same bearing surface as their 200gn swaged SWC, and did not see any increase in accuracy. If anything, I found it much harder to work up a good load and the accuracy was over a very narrow range of charge weights.

If I could afford them, I would love to shoot more 185gn JHPs. I avoid them since I "fear" I might like them too much--so I haven't shot any in about 15 years.

In terms of accuracy of lead bullets, I need to fire somewhere between 4 and 20 rounds from a completely clean barrel to get back to an accurate condition. After that, the barrels stay accurate for 1-5k rounds. All I clean on my 1911s and CZs and clones are the feedramp and the breech.

The series 70 Gold Cup I bought in 1978 has had well over 50k rounds through it and it is as tight and accurate as it was after the first 500 rounds after it left Jim Boland's hands (note: those who know who Jim Boland was will know how "rare" my GC is).

[reichebrown]

I thought it was because the roational mass was farther from the center that made hollow points fly with more stability?

[Poppa Bear]

I think it is a bit of all these posts. Center of gravity/ rotational center/ better base/ air in HP creating perfect nose......

[lcs]

Believe it or not! Round nose bullets can be deflected by cardboard. The holes made by round nose are smaller and less defined. Round nose can also be deflected on steel. JHP cut nice round holes in paper and two hits very close to each other can easily be determined. JHP will hit steel better also. I believe you gain a little accuracy with JHP as others of said.

[Croomrider]

I come from a precision rifle background where ALL match bullets are hollow points. You can easily see the difference on target between hollow points and FMJ bullets. I don't buy the arguments about the air on the nose or the bearing surface or the extra weight being toward the OD. A shorter bullet is easier to stabilize than a longer one. If the bullet doesn't have an air cavity that is off center it should stay stable if the rifling is doing it's job when the bullet leaves the muzzle. It has been proven that the nose is not as important as the base as long as there is not a huge glaring defect. Hollow points are just more accurate because the base of the bullet is the most important part, being the last thing influenced by the barrel and escaping gasses, and the base is easier to control in the process of forming a HP compared to a FMJ bullet.

Mike

Edited July 12, 2012 by Croomrider

[isleman75]

Croomrider finally hit the nail on the head. JHPs cut better holes in the targets and manufacturing tolerances are more tightly held for JHPs. I have a friend/customer that competes with very expensive rifles/bullets/and equipment. He also started to make his own JHPs in 6mmBR and has discovered how truly difficult it is to make them go in straight lines when there are so many things affecting accuracy.

The crown of the muzzle proves infinitely important as the gasses move around the bullet upon exit from the barrel. Also, Croomrider is correct in that the uniformity of the base of the bullet is more important for stability, flight, etc. It is much easier to make a very uniform JHP than to do the same for a FMJ, thus the reason for match bullets always being JHPs.

When it all comes down to the nut cutting, the relatively short barrels and comparatively slow rifling twists we use in our pistol games prove not to be as fickle for accuracy as our rifle shooters' tools. Most of our high end pistols with nice barrels and proper assembly will shoot 2" groups at 50 yards without breaking a sweat, with all types of bullets-lead or jacketed. And with the majority of our shots going down range at an average of 10-15 yards, accuracy is controlled infinitely more by the hands and skills of the shooter, not whether there is a .001" runout in the base of a particular bullet.

[rpd]

For me, I switched to JHP because they have an enclosed base and are about the same price. I shoot indoors a good deal and need to avoid as much lead exposure as possible. Any additional accuracy benefit is just an extra, but for the kind of shooting I do doesn't make much difference. I have noticed the holes are cleaner with JHP.

[racerba]

...longer for the same weight bullet.

IMHO...

Longer is the key to more accuracy. The longer the bullet, the more lands and grooves the bullet has in contact with the barrel producing a more consistent flight path = more accuracy.

Are you implying that shorter bullets will jump the lands/grooves? If not, how exactly does a longer bullet interact with the rifiling in a more accurate manner? It can't spin faster. Does it exit the barrel crown better? Is it less damaging to the jacket during initial rotational acceleration? I seem to recall that some barrels are designed with variable twist grooves to slowly apply rotation, but I thought that was for long guns.

shorter bullets leave the barrel sooner...while longer bullets is still being affected by the barrel...