FMJ vs. HP - Simple Question (I Think) Related to Accuracy

[Sigarmsp226]

So in simple terms help me understand how/why HP bullets that we load are more accurate than FMJ bullets we load.  I ask because I have been very happy with the accuracy I get from 124gr FMJ’s I am shooting at steel out to 35 yards. At 20 yards where I sight in my PCC and Pistols with this load my PCC can produce one hole five shot groups (Half Dollar size) from a rest.....

 

And I have to ask how much more accurate is “more accurate”......  Thanks Mark

[ima45dv8]

I've read for years that the JHPs are more accurate and stable (how much? minor I'm sure) because the center of gravity is further back.

[Joe4d]

Never heard of bullseye guys using hollowpoints. Usually wadcutters, even hollow base ones.   I dont buy in the least that hollow points are intrinsically more accurate than other designs. Open guys like them due to no exposed lead to foul comps. Pretty much their main benifit.

Sounds like the OP's loads are fine. 

[sc68cal]

22 minutes ago, Joe4d said:

Open guys like them due to no exposed lead to foul comps

 

This is the main motivation for using JHPs.

[Silver_Surfer]

Thought that saying was more for rifle bullets than handgun bullets?

[zzt]

Bullseye shooter DO use JHPs, mostly for the 50 yard line.  The Nosler 185 JHP has long been the bullet of choice for serious 50 yard bullseye shooters.  Many use HPs for 25, but not necessarily jacketed.  The Zero 185gr LSWCHP is a very popular bullseye bullet.

 

The reason that JHPs are more accurate the JFMJ is the base of the JHP is more consistent.  The most accurate 9mm bullet I've shot is the 115gr HAP.

[OSP737]

4 hours ago, zzt said:

Bullseye shooter DO use JHPs, mostly for the 50 yard line.  The Nosler 185 JHP has long been the bullet of choice for serious 50 yard bullseye shooters.  Many use HPs for 25, but not necessarily jacketed.  The Zero 185gr LSWCHP is a very popular bullseye bullet.

 

The reason that JHPs are more accurate the JFMJ is the base of the JHP is more consistent.  The most accurate 9mm bullet I've shot is the 115gr HAP.

Bingo!

[noylj]

For inside 25 yards, accuracy is more the shooter and the gun than any special bullet.

I can even get decent groups with plated bullets at 15 yards, but at 25 yards they open up quite a bit for me. Never even considered looking at 50 yards with any of them--no hope based on 25 yard group size.

Out at 50 yards, bullets tend to rate:

JHP

L-SWC/L-WC

FMJ-FN/L-FN

FMJ-RN/L-RN

YMMV, but that is what most folks find.

Why? Have no idea. One would think that moving the center of gravity towards the rear (as a JHP) would make the bullet less stable.

Continue shooting what makes you happy--being happy alone can improve accuracy

 

[gng4life]

3 hours ago, OSP737 said:

Bingo!

+1

[AverageJoeShooting]

i think it depends on what your using them for. uspsa? you will never see any difference no matter what bullet you use. bullseye? definatly want to get every piece of accuracy you can. long rang rifle? again with the accuracy. home defense? whatever you pick up to defend yourself.  

 

Ive been shooting lead out of my open gun for years and ive never had lead fowling...i do also ultra sonic clean so maybe thats part of it. 

[RGA]

10 hours ago, gng4life said:

+1

+2

[RangerTrace]

My understanding is that the JHP bullets will be longer, which gives the bullet more engagement with the rifling.

[Farmer]

15 minutes ago, RangerTrace said:

My understanding is that the JHP bullets will be longer, which gives the bullet more engagement with the rifling.

^^This,, more bearing surface. 

[zzt]

There are lots of theories as to why JHPs are more accurate than say RN FMJs, or lead, or plated.  Noylj mostly got it right, with a caveat.  The lead bullets must be perfectly formed to be more accurate than FMJs, and then mostly in 45.  Dardas 200 LSWC and the Zero 185 LSWCHP are the most accurate lead bullets I've ever shot.  I've tried at least eight other brands and none come close.

 

Back to why JHPs are better.  Firstly, they are formed more precisely.  That gives you two benefits.  One is the base is perfect, or at least way better than any other.  Second is they are more concentric.  The more concentric the less the rapidly spinning bullet will be thrown off target.  Secondly, (and I cannot prove this) is the hollow point traps air and pushes what I'll call a bubble around the nose.  There is a technical term for this, but I forgot it.  I read about this ages ago.  Anyway, the bubble sort of insulates the front of the bullet from the surrounding air, so drift is minimized.

 

I've read a lot about this, but most of the info comes from testing.  On the 50 yard side of our pistol range is a pedestal dedicated to mounting a Ransom Rest.  It gets used a LOT.  It is truly astonishing how much difference the groups of various lead bullets are.  The Zero 185 LSWCHP is swaged, and swaged is generally more accurate than cast.  The Dardas was cast, and very, very well done.  Too bad he retired.  I only have 2000 left from the last bulk order.  The Nosler 185 JHP beats them all at 50 yards.  The Precision Bullets 200 TC and SWC in 45 are superb coated bullets. 

 

Now, I have not as much experience with 40 and 9mm bullets.  In 40, the Rainier plated bullets were just as accurate as the Montana Gold 155 JHPs at 25 yards.  Precision's 185 RNF is excellent. 

 

In 9mm, EVERY JHP bullet I've shot has been more accurate than RN.  Rainier is out of business.  Berry's plate and RMR plated are great.  Everglades is a little behind, and X-Treme is way behind.  In poly coated, stuff is all over the map. Summers Industries 125 RN coated and Roger's Purple PC bullets are good.  Acme is so-so as are a bunch of others I was given to try.  The absolute worst were the J-Ames 124gr with the proprietary coating.  Not only did them smoke, the couldn't do better than a 12" group at 25 yards.  Unfortunately, I bought 1000 124 and 500 135 because I was assured they would not lead up a comp.  I shot about 200 and gave the rest away.  I haven't tried Precision yet, but I'm sure they will be just as good as the 45 and 40 bullets.

 

[Banacek]

When I was choosing a bullet for USPSA, I tested both the 124gr JHP and FMJ from Montana Gold bullets.  The JHP actually had a higher velocity under the same powder charge and it was easier to make power factor.  I never heard that JHP were more accurate and for my game not sure I need the extra accuracy.  

[superdude]

  double post

Edited December 20, 2020 by superdude

[superdude]

Just now, superdude said:

 

JHP bullets tend to be shorter than RN bullets from the same manufacturer (from the 9mm bullets I've measured).

 

[Darrell]

JHP's are more accurate than FMJ's in my testing. Someone mentioned that HP's loaded with the same powder charge was faster. That's probable because the bullet is seated deeper in the case raising pressure. I load PD 124 JHP's at 1.080 where as PD loads there Pro ammo at 1.100. I find every bullet has a sweet spot, doesn't matter whether JHP's or FMJ's when it comes to optimum OAL. Get out and do some testing and see for yourselves. 

[RGA]

18 hours ago, Darrell said:

Get out and do some testing and see for yourselves. 

 

+1!

[noylj]

>Noylj mostly got it right, with a caveat.  The lead bullets must be perfectly formed to be more accurate than FMJs, and then mostly in 45.

 

Sorry, but a basic assumption about all cast bullets is that the base is completely filled out. If so, I get very good accuracy even with wrinkly bullets out to 50 yards. Swaged lead bullets, like all jacketed (swaged copper/lead) bullets, have the edge for overall consistent geometry and weight.

That's why, since I load for accuracy, even my HOT .38 Super loads are either JHPs or commercial swaged lead (12-13 BHN).

I have never had a FMJ reach the accuracy of my own cast bullets or commercial swaged lead bullets. Again, YMMV and I can only speak from MY experience.