One bullet wieght per caliber and gun?

[KenC]

I was surprised by the enormous difference in POI that a change in bullet weight causes. I found that at 50 yds, a 55gr 223 hits 7" lower than a 62gr 223 in my Mini-14. I then looked into the matter and learned that heavier bullets hit higher because there is less upwards momentum imparted from the barrel with faster bullets.

IMHO, this difference in POI is too much to compensate by changing my aim point or adjusting my scope without sighting in again.

What do most shooters do? Just stock up on one bullet weight per caliber and gun -- the one that shoots tightest?

Ken C

 

[243winxb]

Handload and control velocity. Bullets of the same speed , should be close at 100 yds.

 

[Blue68f100]

I have scope dope to make adjustments when shooting the non-standard round in a gun. The most change I have run across is 1.5" in elevation, with 0.5" windage. I set the scope up for it's intended use, whether hunting or target. Most of my hunting loads are with heavier bullets. I have load data cards with all the ammo and which includes which gun/scope was used. Then I make notes when I shoot a different gun as to what needs to be adjusted. Just remember to reset it back to the original. Helps to zero the turrets, those with stops are better yet.

 

[FROGO207]

First welcome to THR.
I do try to find the most accurate bullet for each firearm I own---just because. Yes different bullet weights will give different results but by reloading them yourself you can tailor the results so the impact area is close. I have found that even within the same weight and brand a different style of bullet will shoot better or worse than others in a particular firearm. To me that is the fun of hand loading/reloading. Finding the best combo to shoot the best on target at the range I want it to. Even two firearms made with sequential serial numbers will shoot the same bullet quite differently as a rule. Handguns seem to be more tolerant to bullet differences than long guns, at least from what I have observed over the years.

 

[cfullgraf]

Generally, once I find a bullet/powder combination that works well in one of my rifles, that is all I shoot in it.

Sometimes, I get an idea that I'd like to shoot a bullet of different weight/construction and I start the optimization process all over. Once I find THE load, that is all I shoot I that firearm.

As a side note, I have a shelf full of open, partial boxes of bullets.

In a couple of instances, I have found a bullet/powder combination that works well in a couple of firearms. For example, for prairie dogs, I use a bolt action and AR-15, both chambered in 204 Ruger. With the same ammunition, I get nominal 3/4" groups at 100 yards. I might be able to improve on that for each rifle, but it is convenient to only have to bring one type of ammunition.

 

[jmorris]

Write the data down, including the number of “clicks” it takes you to god from one load to the other. Now you just have to remember what load the scope is dialed in for...

 

[Infidel]

I was surprised by the enormous difference in POI that a change in bullet weight causes. I found that at 50 yds, a 55gr 223 hits 7" lower than a 62gr 223 in my Mini-14. ....

That seems excessive, as if maybe there's something more than bullet weight going on there.

 

[KenC]

That seems excessive, as if maybe there's something more than bullet weight going on there.

The 62gr is Silver Bear SP (steel/bi) and has a stated muzzle velocity of 3045; the 55gr is Partizan SP (brass/boxer) and has a stated muzzle velocity of 3248 fps. Both gave 1" groupings of three at 50 yds.

The Mini-14 is an oldie and the scope mount is not as positive as I would like, but was tight. I did then shoot a couple of rounds of 64gr Fed Power-Shok SP (3080 fps) and it hit very close to the 62gr.

Ken C

 

[Toprudder]

That seems excessive, as if maybe there's something more than bullet weight going on there.

That is what I was thinking. Could be the barrel whip, one bullet is leaving at the top of the swing, the other at the bottom.

I know a guy that installed a clamp-on muzzle brake on his bolt action rifle, and moved the POI 9" at 100 yards. It did tighten up the groups a little.

 

[tightgroup tiger]

Generally, once I find a bullet/powder combination that works well in one of my rifles, that is all I shoot in it.

That's what I do with all my rifles. I have one load I use for everything with each rifle. Of the 22 guns I own, I know what shoots best in each one.

I do play with different powders but only in my handguns. My bulk loads I rely on though are all proven loads that I don't mess with.

 

[JeffG]

Generally, once I find a bullet/powder combination that works well in one of my rifles, that is all I shoot in it.

That right there...

 

[LoonWulf]

Ill likely shoot the same bullet in every cartridge that i have in that particular caliber, but I almost never shoot multiple weights from the same cartridge.
If i DO have some random weight bullets ill shoot them up using a generic load. Right now, in my 7Mag, im going to burn up some 160s. Then ill resight for the the 120Vmax i forgot to send to buddy that were for my 7-30. When they are gone ill re sight to my 162s.

 

[irishlad]

The only I gun I shoot 2 loads out of is my 280 rem. rifle. 140 gr for deer and 160 gr for elk. I have to sight it in when changing.

 

[ArchAngelCD]

I found that at 50 yds, a 55gr 223 hits 7" lower than a 62gr 223 in my Mini-14.

For real? I have never experienced that much of a spread especially at only 50 yards. Heck, both bullets should still be climbing at only 50 yards. The difference should be less than a half inch.

 

[Toprudder]

I have 3 guns in 223/5.56 - a 20" precision rifle, a 16" carbine, and a 8.5" pistol. I would not consider using using the 75gn loads for my precision rifle in the pistol. I would not consider using the reduced recoil/flash 52gn loads for the pistol in the precision rifle. I do have some 55gn loads that work well in both the 16" and 20" rifles - at 100 yards.

When it comes to regular pistol calibers, I do like to make one load that works well across all of them, but then when I throw a 16" 9mm carbine in the mix, I have a special load that works very well in that.

My S&W 625 45acp revolver shoots very accurately with bullets that don't feed well in my semi-autos, loaded much longer than will plunk in the semi-autos. When they come off the press, they immediately go into moon clips, that way I can't load them in my other guns.

 

[GRIZ22]

Mini 14s are fairly accurate...for the first few shots. If your barrel gets heated up that could account for your difference in poi.

What range did this occur at?

 

[Fine Figure of a Man]

7 inches at 50 yards, 14 MOA, is a lot. I would double check the scope and mounts and shoot some more groups with both bullets.

 

[243winxb]

7" lower

Not normal, as others have said.

More testing is needed.

 

[Varminterror]

7” at 50yrds? Way too much POI shift at 50... For comparison, I use cheap 50grn Rem/UMC JHP’s as fouling shots and to get me on steel out to 500yrds on 66% IPSC Targets, then swap over to my work-up loads, most recently with 73grn ELD’s and 77SMK’s (new barrels). My POI shift doesn’t drop me off of a 12”x20” target at 500, let alone shifting 7” at 50yrds.

Personally, yes, I tend to figure out one load per rifle. My application tells me which bullet(s) I need to try and how fast I need to push it, which tells me the cartridge and which barrel twist I need to run - then the rifle gets bought/built. I have a couple rifles with multiple loads - for example, a 60grn partition hog/deer load, and a 50grn Vmax coyote load. I swap scopes instead of shifting my zero. I do have a 77SMK load for several rifles, which I simply rezero from my others. But that said, I turn my elevation knob for almost every shot I take, so rezeroing to change loads isn’t a big deal.

 

[Toprudder]

I have a Mini-30 that the first shot groups about 1-1.5" away from the following shots, @ 50 yards. Something about manually chambering a round changes the POI.

 

[hdwhit]

KenC wrote:
What do most shooters do?

My standard self-defense and hunting load for 223 in a Mini-14 uses a 60 grain Hornady Spire Point bullet (available as either soft point or hollow point). At around 13 to 16 cents each, this bullet is fairly expensive. To compensate, I have developed a load using a 55 grain full metal case pulled bullet which runs me about 6 cents each. By developing the load from scratch and ending up with a velocity slightly higher than the 60 grain load (which I suspect is necessitated by the lower ballistic coefficient of the 55 grain bullet when fired in the upper 2000 fps velocity range), I was able to achieve the same point of impact at 100 yards for both loads out of the Mini-14.

I cannot explain the 7 inch difference you experienced and you didn't provide any particulars about your loads (i.e. powder, charge, bullet brand, primer type, etc.) that would aid in a diagnosis. As it is, all I can suggest is picking either your 55 or 62 grain load and standardizing on it and then redeveloping the load for the other bullet until you have closed up the difference in point of impact. There is a lot of practical knowledge and more than a little wisdom available on this site, so if you want to provide more detail about your experience, you will certainly find help here.

 

[Blue68f100]

Almost like one was subsonic and the other super sonic to have that much difference.

 

[KenC]

7 inches at 50 yards, 14 MOA, is a lot. I would double check the scope and mounts and shoot some more groups with both bullets.

Did that, same result: 7" low fpr the 55gr and grouped together.

With my T/C Compass BA, the groupings for the different rounds are only 1.5" apart, at most.

This is an old Mini-14 with the thin barrel. As suggested, barrel whip could be the explanation.

Ken C

 

[jmr40]

I shoot 130, 150, 155, 165, 168, 178, and 180 gr bullets in my 308's. With my hand loads, at 100 yards the POI is close enough to not matter. In fact out to 400 yards the difference is only a couple of inches.

I shoot 50, 52, 55, 60, 62, 69, and 75 gr bullets in my 223's and there isn't enough difference at 100 yards to matter.

I suspect the difference isn't the bullet weight, but significant differences in the loads. Or the rifle.

 

[Toprudder]

Did that, same result: 7" low fpr the 55gr and grouped together.

With my T/C Compass BA, the groupings for the different rounds are only 1.5" apart, at most.

This is an old Mini-14 with the thin barrel. As suggested, barrel whip could be the explanation.

Ken C

Those old thin-barrel Mini-14s have a reputation as being inaccurate. Have not experienced it myself, though, I don't have a Mini-14.

I do have an older Mini-30, that everyone told me would have a .308 bore. After working up loads using .308 bullets and getting somewhat mixed results, I finally got around to making a cast of the bore and found out that it is, in fact, a .310 barrel. So, you can't believe everything on the internet.

I hope you figure out the problem, or at least a way to work around it.