6mm Remington Trajectory etcetera

[raisedin99]

Young neighbor stopped by with a question as he has in the past, he has recently purchased
a used but new to him deer rifle in 6mm Remington with now 15 rounds of ammo after
shooting it a couple times and no ammo to be found locally but naturally wants to use his
new rifle in the up coming deer season.

He said the rifle was shooting dead on at 25 yards and wondered if that was good
enough for a 100 yard shot. My thought was it was shooting high but I don't have any reference
materials to substantiate that thought. I told him I'd forward his concerns to where it might
get a reasonable answer. Anyone care to join in with the knowledge we don't have.

Thanks,

terry.

 

[Rodan]

Too many variables for a solid answer, but almost any scoped rifle zeroed at 25 yards will have a very high POI at 100 yds.

 

[DWalt]

It can't be answered that simply because it depends on the bullet (weight and type), the MV, and the distance of the scope above the centerline of the bore. Having said that, a 25 yard zero would probably be OK for deer hunting at 100 yards. Firing one shot from a bench rest at a target 100 yards out would probably answer the question.

 

[ReloadforFun]

As stated above, more information about the ammo to have a conclusive answer.

However, looking at the Hornady 95gr 6mm Remington, with a 25 yard zero, the bullet is about 3.2" high at 100 yards.

 

[gwpercle]

Only one way to tell ... set up a target at 50 yards , 75 yards and 100 yards ... and CHOOT EM' ! as Troy Landry was say ...

Troy also says 1" high @ 100 yards is good for open country ... down here in the swamps of Louisiana 75 yards is a Long Shot ...and be careful not to hit one of the dogs !
Gary

 

[raisedin99]

Sorry folks, I have no idea as to what the ammo is, he just mentioned that he

didn't have very many (15). I should have asked those questions... thank you all for

your comments that I'll pass on once I see him again.

terry

 

[4barrel]

Also it depends on how high the scope is over the barrel. The scope is looking at the target and the barrel is pointed up. The back pages in an older Lyman reload manual has this info. <0 and bullet impact at different yards with different bullet weights.> With a low profile scope and the right bullet it could be close but the bullet would probably print a little high @100.

 

[Buick]

The crowd i hunt with swears by a dead on at 25 yards zero. They shoot a multiple of the most common high powered deer rifle calibers. All have no trouble killing deer from 10 to 300 yards. I believe a couple of them were in the army years back and they can shoot quite well.

 

[ReloadforFun]

Generally the bore line points down compared to the line of sight, and recoil has the bore line pointing up as the bullet exits.

This is easily seen with a couple of dowels - one in the bore and the other along the sights.

 

[bigmoose]

If memory serves me correctly (not always a sure thing) I may have a box of 6mm Rem (formerly called .244 Rem) that I would gladly send off to a young hunter. FREE. I am away from home for 10 days on business.

OP, send me a PM if your neighbor is interested.

-Cap

 

[DWalt]

The 6mm and the .244 Rem cartridges are essentially the same. The early Remington rifles chambered in .244 had a rifling twist which was too slow to adequately stabilize heavier bullets. They saw it as a varmint rifle, not a deer rifle. They later changed to a tighter barrel twist and also changed the name of the cartidge. But the damage to sales had already been done, and the .244/6mm Rem never really caught on with hunters. The .243 Winchester had similar ballistics, but Winchester used a tighter twist from the beginning. So the .243 Win won the battle for hunter acceptance because it would from the beginning stabilize heavier bullets better, and therefore could be used by both varmint and deer hunters.

 

[DWalt]

The crowd i hunt with swears by a dead on at 25 yards zero. They shoot a multiple of the most common high powered deer rifle calibers. All have no trouble killing deer from 10 to 300 yards. I believe a couple of them were in the army years back and they can shoot quite well.

For deer hunting, at least in most parts of the country, if you can hit a paper plate-sized target at 100 yards, your rifle is sighted in well enough. Hitting 2 inches high at 100 yards is not a disadvantage in the real world.

 

[BB57]

There are a fair number of variables but it’s not rocket science.

Sight height is a big factor but if your in the ball park it should be fine. Unless he’s using one of those really stupid look under scope mounts the center of the scope will be roughly 1.7” above the bore.

With a 1.7” sight height and a factory 100 gre Remington PSP and a 25 yard zero, the rifle will be shooting about 3.5” to 4” high at 100 yards and it’ll be zeroed at about 300 yards and be about 5” low at 355-360 yards.

Most 100 gr factory loads at 3100 FPS will have very similar ballistics. Even the Federal 80 gr SP at 3400 FPS will be fairly close - about 4” high at 100 yards, zeroed at 350-355 yards and 5” low at about 410 yards.

The major problem that I see is that at 25 yards it needs to be *precisely*zeroed at 25 yards to be zeroed at any significantly longer distance. By precise I mean a very tight group exactly zeroed at 25 yards. Being just a 1/4 inch off up or down, or worse side to side, will cause big problems at 100 plus yards.

In that regard th value of a 25 yard zero is to approximate a longer range zero (like the above mentioned 300 yard zero). However it then needs to be verified at a longer range. In the case shooting at 100 yards and confirming it is really 3.6” high at 100 yards and precisely centered for windage is important.

——

In general the .244 Remington/ 6mm Remington is about 100 FPS faster than the .243 Winchester with any given bullet weight.

As noted above the slow twist in the .244 Remington chambered rifles was optimized for lighter weight (70-90 gr) Varmint bullets, and it would not adequately stabilize the 100 gr spire points designed for and preferred by most hunters for medium size game like deer and antelope.

The 6mm Remington Chan breed rifles used a faster twist that would stabilize 100 grain spore points.

That said, I was a big fan of the old Hornady 87 grain BTSP in both the .243 and .244 on antelope. It both started out faster and retained velocity better than their 100 gr flat base spire point and out past 300 yards it had better terminal ballistics.

Hornady seems to have agreed about the utility of lighter 6mm bullets on medium game as while their 87 gr V-Max is a varmint bullet they now offer a 90 gr ELD-X, a 90 gr CX and a 95 gr SST in addition to a 100 gr BTSP and an 103 gr ELD-X for medium game.

 

[pantannojack]

Theory is for Professors

Find a 100 yd range (improvise if necessary). Fire one shot from a dirty cold barrel. Do not rest the rifle on the bbl, but the fore stock. Do not adj the scope unless it is more than 4" off center (interpretation needed). This is your point of impact in relation to your point of aim. Shoot more if you find more ammo, but this should work out to 100 yds in a pinch.

 

[Krogen]

Quicktarget shows for a representative 6mm Rem load, that a 25 yd zero prints a bit over 4" high at 100 yds.

 

[BB57]

Quicktarget shows for a representative 6mm Rem load, that a 25 yd zero prints a bit over 4" high at 100 yds.

This is where starting assumptions like sight height above the center of the bore matter with short range zeros like 25 yards.

For example with the Remington 100 gr PSP load above at 3100 FPS, a 1.7” sight height results in a +3.6” point of impact at 100 yards.

A 2.0” sight height raises the POI to +4.5” at 100 yards with the same 25 yard zero.

A 2.3” sight height will raise it even more to +5.4” at 100 yards.


That’s because the higher the sight height the farther below the line of sight the bullet starts and the more it has to rise to be “zeroed” at 25 yards. The resulting higher angle of departure with greater sight height means a higher mid range trajectory which means the bullet will be farther above the point of aim at 100 yards.

Conversely with something like an iron sighted BLR in .244/6mm Remington a low .75” sight height and a 25 yard zero will put the point of impact just .8” above the point of aim at 100 yards.

——-


With a longer initial zero range sight height becomes much less of an issue.

For example with the .75” sight height in the last example and a 100 yard zero, the the bullet will be 5” low at 221 yards.

Put a scope on it with a 2.0” sight height and again zero at 100 yards and the bullet will be 5” low at 244 yards. That’s not a huge difference.


Step out the zero range to 300 yards and you’ll see the .75” sight height results in the bullet being 5” low at 352 yards and with the 2.0” sight height the bullet will be 5” low at 354 yards - almost n difference at all.

In short, the shorter the zero range, the greater the change in angle of departure with sight height, and at ranges much past 200 yards sight height has very little effect.

 

[bigmoose]

Believe it or not my Remington 722 in .244 Remington ( with the 1 in 12 twist barrel) shoots Federal 100 grain factory ammo just fine. At 100 yards it’s MOA. I’m thinking it’s not so much the weight of the bullet but the bullet coefficient? Anyways, it has a Redfield Revolution 2x7 on it, which in my opinion is a great scope at a great price. The clarity and brightness of the optics are amazing.

I do carry it deer hunting on occasion, but a decent buck has yet to appear within its range.

 

[WR Moore]

It's not really the weight, but the length of the bullet that matters with respect to rifling twist. Since heavier bullets are generally longer, most folks just refer to weight.

 

[BB57]

Believe it or not my Remington 722 in .244 Remington ( with the 1 in 12 twist barrel) shoots Federal 100 grain factory ammo just fine. At 100 yards it’s MOA. I’m thinking it’s not so much the weight of the bullet but the bullet coefficient? Anyways, it has a Redfield Revolution 2x7 on it, which in my opinion is a great scope at a great price. The clarity and brightness of the optics are amazing.

I do carry it deer hunting on occasion, but a decent buck has yet to appear within its range.

As noted above it’s the length not the weight that impacts stability.

It’s also air density. Two things drive density altitude, temperature and pressure. Hotter weather and higher altitude produce lower air density and better stability than lower altitude and cold temperatures.

Looking at all three:

- Hornady made (and still does) a 105 gr RN bullet that stabilized just fine in the .243, but that’s because it was actually shorter (.905”) as their flat base 100 gr spire point (1.062”) or their 100 gr BTSP (1.066”).

- in your example of 100 gr bullets shooting well at 100 yards in a 722 in .244 Rem (1-12 twist) stability was probably marginal but still gave good performance under your specific conditions.

- bullet length varies as well. Sierra makes a 100 gr semi point at .908”, while their 100 spitzer 1.041” and their 100 gr match king is 1.078”.

- that may not have been the case at lower density altitudes or cold temperatures that produces lower density altitudes.

- velocity also makes a difference and shorter barrels with less velocity result in less spin rate and less stability.

——-


Some examples.

- In a 1-12 twist at 3100 FPS the fairly long 100 gr match king isn’t stable at sea level (Specific gravity = 0.967) and 59 degrees F. With an SG less than 1.0 it’s theoretically unstable.

- However in the same rifle on a 70 degree day at 3000’ it’s now marginally stable (SG = 1.10).

- in contrast the short 100 gr semi point is more stable even at sea level and 59 degrees with an SG = 1.27. Even at sea level and 0 degrees the SG=1.13 and it’s still more stable than the 100 gr SMK at 70 degrees and 3000’.

- in the .243 with a 1-10 twist but only 3000 FPS is marginally stable as well at 0 ft and 0 degrees F but more so than any of the above with an SG of 1.35. At sea level and 50 degrees the SG is now 1.50 and it meets the theoretical threshold for being “stable”.

In any case, the Berger stability calculator os pretty easy to use as long as you have the length and velocity of the bullet and it will give you a good idea what to expect.

https://bergerbullets.com/twist-rate-calculator/

 

[Johnnu2]

Once BigMoose sends him the ammo (our collective THANKS to a good man), you can tell your young friend: "you'll be fine as is; aim and fire".

IMHO,
J.