Velocity question for some of the experienced reloaders

[flyingfrog509]

Still fairly new to reloading. Starting to work up a load for my son's REM700 SPS .308 (20" barrel 12:1 twist)

We have shot several factory loads and have noticed that the 180's shoot much better than the 150's. Then to throw a monkey wrench into it all we reloaded some 110 varmint loads & 130 youth loads that also shot well.

The common factor in all the good groups was the velocity was around 2550-2590 FPS found in the 180's and the 130 youth hand loads.
130's 2542FPS .38" group (hand load)
180's 2570FPS .54" group (factory winchester)
180's 2590FPS .35" group (factory)
110's ???FPS .75" group (just luck very first loads just for fun)

all other 150's running 2800-2900 over 1" groups.

So with all of that said...have I found the sweet spot that the barrel likes OR is it a fluke? I can't understand why 150's will not shoot, yet 130 & 180's will. I don't know what to say about the 110's because I didn't crono them.

Thoughts from some old timers? Should I stick with finding handloads that match the 2500-2600FPS range? I'm afraid that for hunting that maybe the bullets will not expand well at the lower velocities when reaching out past 200 yards. Target practice who cares (unless there are some down side of shooting slower bullets other than having to drop like 60" at 500 yards)

 

[Bear44]

If your son can handle the recoil of the 180s at 2550 you are fine for expansion with the right bullet. Bullet design selection is the most important factor for terminal ballistics. That MV for 130s is slow and you will need to be more careful about bullet selection because the lighter bullet will slow much faster than the 180s at long range. You could probably find a 150 load that shot more accurately with some effort.

Now for a reality check. 1 MOA groups are fine for hunting. Remember that 1 MOA is the standard for accuracy for the US Marines Scout Sniper rifles. Do not compromise the terminal ballistics you are looking for to get groups that are smaller when it will have no practical use in the field. To give you some perspective. 1 MOA translates to a group the size of the palm of your hand at 500 yards. Do you need better than that?

I'm an accuracy freak, but I also keep it in perspective. I try to find a sub 0.5 MOA load for every rifle I own, but I will not sacrifice terminal ballistics to get it in my hunting rifles.

 

[Chuckdog]

Looks like a great shooter to me.

As Bear pointed out one hole ain't necessary for a great deer round. What I look for most in a deer combo is 1st shot consistency. I want to know that 1st one will always hit the same place.

As already noted, pick your bullet's construction to match your velocity range and you'll be fine with any of them.

H4895 works great for lower velocity rounds. I've also found SR4759 to be a fantastic performer when you need to get em' a little slower than you can with 4895.

I've found the Nosler 125 grain ballistic tips to be excellent whitetail medicine at reduced .308 velocities. I'm loading them @ 2350-2375 fps out of 18" Model 7's.

 

[rbstern]

all other 150's running 2800-2900 over 1" groups.

A .35" group with factory loads? Has that rifle been completely worked over by a world class riflesmith? Are you sure your calipers are working correctly?

What powder and bullets are we talking about for the handloads? I'd slow the 150s down by subtracting a grain or two. It simply may not like 150s at top velocity.

But, honestly...who cares? If I was shooting .35" groups with factory ammo, I'd be going to every local range I could find, with a wad of cash in my pocket, and starting every conversation with "Bet you I can..."

 

[flyingfrog509]

Believe it or not...bone stock Rem700 SPS Tactical 20" 1:12 twist heavy barrel. Guess the trigger has been worked over down to just a tad over 2 pounds.

Thanks for the reality check on hunting accuracy. My son got the SPS to hunt and go to the range with. We had problems with some factory rounds that really threw us off early on...like core-lokt 150s going in and out about the same size. Didn't matter because we are both bow hunters so double lung shots even with tiny holes drops a deer in less than 100 yards. The 180's were the first factory round that did damage, so that is what he hunts with. Stick with what works to fill the freezer.

On the flip side at the range it is all about tiny holes. I'll end up posting some pictures to add on to his review of his gun...just because I know it is hard to believe some of the groups. Now just to be clear...these have been three round groups so statistically it is much easier to get small groups vs. 5 or 10 shot groups.
The gun seriously shoots just about anything we've ever put through it at 1" or less with few exceptions.

Loads thus far:
110 Sierra varminter - CCI200 - Accurate 2495 (42.3-42.6) - OAL 2.328 - Winchester brass (new)
130 Hornady Interlock - Win WLR - H4895 (37) - OAL 2.685 - Mixed military brass

The light loads were for a friend's son who is recoil sensitive, we just had to try a group.

SO WITH ALL OF THAT SAID....HOW DOES ONE SELECT BULLETS TO THE VELOCITY? I've seen a few bullet manufatures that list some data on speeds, but typically I don't see that on the box or in the reload manuals. Is that just an experience thing. For hunting right now I'm hard pressed to change from the factory 180's because they work. The boy child is amazingly not recoil sensitive and likes to shoot things like 300 win mag, 460 smith, 44mag. Either way I limit his large caliber shooting to just for fun.

 

[flyingfrog509]

Hey just to make sure I'm not blowing smoke...groups are measured bullet center to center...right?

 

[rbstern]

You can measure center to center, but it's easier and more accurate to measure the farthest spread to the outside edges of the holes, and then subtract bullet diameter. Example: If you have two holes next to each other, with the widest measurement to each of their opposite, outside edges being 1", you'd substract .308" (for .30 cal), and you'd have a .692" group size.

For the smaller group sizes you are describing, it's basically one slightly enlarged hole. 3 shot groups are fine as long as those groups are consistenly in that size range. It's not accurate to say the rifle shoots .35" groups if it does that once every five groups, with the other groups being two or three times the size.

I presume you are shooting at 100 yards?

 

[flyingfrog509]

Yes, 100 yards.

I'm going to try the edge to edge measurement, that has to be easier and more accurate. Right now the groups aren't that good all the time but that has more to do with my son than the gun. He started out shooting about 2" groups and has gradually brought them down. The 130 grain hand load was a one time deal because I only made 10 shots and we were sighting them in my buddies rifle for his son to shoot so we did a three shot group with the left overs.

Think I'm going to continue to track and save the targets and do a write up on it once we have a good collection of targets. His last group was his "certification" group before hunting starts. Each year I have both children shoot a group cold and based on that tell them how far out they can shoot till we do it again. So whatever the group is times how ever many yards equals a four inch group is how far they get to shoot. My daughter only did 1.75" group this year so I told her she is good out to 225. I just like to have a factor of two because the field is never as easy to shoot accurately.

Thanks for all the help.

 

[squirrel]

Think I'm going to continue to track and save the targets and do a write up on it once we have a good collection of targets. His last group was his "certification" group before hunting starts. Each year I have both children shoot a group cold and based on that tell them how far out they can shoot till we do it again. Thanks for all the help.

Both sound like good practices to me. delightfully reasonable.

On your groups, Ive seen this before. I could take 10 factory rifles in identical calibers with no modification, but one of them will shoot a half inch or better. The rest are perfectly acceptable but not like that lucky one. Its just a symptom of mass production, it happens. Sounds like his rifles a keeper. Id also give 165-168 gr bullets a try. They are accurate in the majority of .308's. I have in the past used SST's, HP gamekings, and Nosler Ballistic Tips. All have worked on local critterage with good results . Im working loads for a new .308 I obtained this month. So far so good with these old stand-by's.

 

[sc951]

I load 168grn sierra match kings on top of 45.5 grns of Varget. Average around 2600fps and ultra accurate.