308 Loads need help with results


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biga972
September 19, 2011, 11:26 AM
I have just started to reload for my .308 DPMS....Now my question is this at 50 yrd same hole but at 100yrd i get about 5" group....Am I wanting to much out of this gun??:confused:

My load is 41.5 gr tac with a 170 gr pulled bullet. My first thought was the bullet but most every one seems to have good luck with them. These are the pulled bullets from rmrbullets.

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rodregier
September 19, 2011, 11:52 AM
Barrel twist rate?

biga972
September 19, 2011, 01:09 PM
16" 1:10

Dave P
September 19, 2011, 01:12 PM
Get some good accurate bullets; SMK, Nosler CC, something like that. Military bullets are not known for great accuracy.

MEHavey
September 19, 2011, 01:38 PM
Recommend going to 168 (or 175) SMKs and 42.5gr/IMR4895 as a calibration load.
That should give you an expectation starting point.

cougar1717
September 19, 2011, 02:02 PM
Your load obviously just doesn't like 100 yd targets. :)
But you do have to start from a known point. If you're in the situation you're in (new gun, new load) and you don't have an accurate load worked up already, it may benefit you to just buy a box of factory ammo (it doesn't have to be expensive) to set your expectations.
Trying to work up with pulled bullets can be a problem just because of the bullet variation. Ideally, you would want to try the SMK/4895 combination since it's a standard for .308 Win. A lower cost alternative would be a Sierra Prohunter or Hornady bullet with the Tac you already have.
Another wrinkle could be your optic. The OP didn't state if it was a scope, red dot, or irons. I would try to diagnose the problem one thing at a time, starting with the bullet, then the powder, primer, case.

biga972
September 19, 2011, 02:25 PM
I did some research and found that the bullets where pulled 175 smk's. This was all done via a 3x9 leupold scope.

I am going to pick up a box of factory ammo this week to get a base expectation for the gun.

Sin City Shootist
September 19, 2011, 03:47 PM
41.5 Tac and a 168gr hpbt is a good combination. I would probably look at your optics for issues, loose screws, bad glass. If that's good, maybe try loading a bit longer, say 2.820.

biga972
September 19, 2011, 04:45 PM
How could the glas be the problem am same hole at 50 yrds.........If glass was the problem I do not think I would be able to do this....I would think.

Just asking I have heard this once before on a different forum.

scythefwd
September 19, 2011, 04:48 PM
if he is one holing at 50y.... and 5" at 100.... its not the load. id go back and see if you can repeat at 50y again.

im leaning toward a base or ring worked loose during the 50y trial. bullets go in a generally straight line. They arent going to spontaneously spreading rapidly once the get past 50y. for a 5" group at 100y, he should be seeing 2.5" groups at 50.

popper
September 19, 2011, 05:30 PM
It was trigger pull and scope moving for me. I stared with 150 rem SP, now use 150 sierra 150 SPP with H335 or H4895. Scope mount was PITA till I put a 6 screw mount on it (3x9). I was good at 50 but concentration and wiggle at 100 was bad. Another shooter with my rifle put a whole mag in the 9 ring , first time shooting an AR, before I changed the mount. If you can shoot it better than the gun, try going up and down a gr. of powder to see if it is the load. I just ordered a short upper for it, supposed to be immediate delivery from Midway, but checkout showed a 10 day delivery. Hope it isn't coming from China. I'd advise practicing more.

medalguy
September 20, 2011, 12:57 AM
I agree with scythefwd: The spread at 50 yards should be half the spread at 100 yards. If not there's something else going on besides the ammo. If you're using a scope, I'd look real hard at that. Scope, rings, mount.

biga972
September 20, 2011, 09:56 AM
Scope is tight, I did go back to 50 and was still holding same hole ......This is what has me thinking its the load.

Eb1
September 20, 2011, 10:37 AM
Could be that you do not have the same POA for each shot. Maybe your gun is angled a little differently on each shot, and @ 50 yards they bullets are crossing paths at the same spot, but @ 100 yards you see the results of not having the same POA to POI issues.

scythefwd
September 20, 2011, 11:30 AM
Parallax issue?

popper
September 20, 2011, 12:22 PM
Parallax should cause off center group, not scatter. Trigger causes left/right stringing, breathing causes up/ down string (generally). Bad crown, bad bullet base, barrel whip, bullet instability, loose pins on AR, (bad load), bad shooter cause scatter. Spot on at 50 indicated crown, bullet, pins and barrel are OK. If the holes @ 100 are nice and round, that indicates stability is OK, leaves the shooter. Check hold on handguard, shooting from bipod or SB? Trigger pull is heavy.

Clark
September 20, 2011, 12:52 PM
I struggled for 10 years trying to get from 6" groups to 1" groups at 100yards in my 308s.

There is a long list of things on the internet to get a rifle from .3" to .25" that will do no noticeable good in getting from 6" to 1".

Here are things that WILL help:
1) Don't shoot when it is windy. A steady 6mph wind is ok, but not a gusty 6mph wind. Look at surveyor tape. It should hang straight down.
2) In about half the guns I have or see that won't shoot, the screws clamping the scope mount to the receiver are lose. A typical symptom is two holes touching over here, followed by two holes touching over there.
3) Dry fire with cross hairs on the target. Verify that the cross hairs stay on the target when the trigger is pulled.
4) Clean the Copper out of the barrel. Looking into the muzzle at an angle, there should be no Golden red streaks.
5) Use good bullets. Vmax bullets seem to work well for small groups in many calibers.
6) Check for parallax. Look at the target through the scope and move your head slightly off scope tube axis. Do the cross hairs move on the target? If the cross hairs move, then move the head back until the image is smaller then the eye piece and keep the image centered in the eyepiece.
7) Bent brass necks. Expander balls pulled through the neck in the same process as sizing the neck will bend the necks. This can increase group sized by 2". New brass does not have bent necks. Brass sized, after firing, without expander balls don't have bent necks.
8) Seat the bullet long enough to reach the lands, if possible.
9) Feed the ammo single shot, so it does not get bent or beat up feeding from the magazine.
10) Shoot slowly to keep the barrel cool.
11) If the barrel is not floated, be very careful that the fore end of the rifle is supported consistently from shot to shot.
12) Usually lighter bullets get better groups. The exception is bad handloaders with eccentric ammo with good recoil management shooting will do better with the longer bearing surface of heavy bullets.

dprice3844444
September 20, 2011, 12:58 PM
ask the manufacturer if they have an ammo reccomendation.try federal first

gamestalker
September 20, 2011, 01:16 PM
A 50 yd. sight in isn't a realistic distance to sight in from for extended distances with a high velocity bullet, and even more so for a light weight bullet. A high velocity high powered rifle bullet needs time to stabilize. The distance it needs to stabilize is based on several pertinent elements of harmonic distortion such as velocity, bullet weight and other relative characteristics of the projectile, barrel type and grade and twist, bullet jump to the lands, brass characteristics, and powder burn rate to name a few.
Of course there are multiple other elements that can cause these inconsistencies as well, most have already been discussed above.

biga972
September 20, 2011, 01:51 PM
the 50 yrd was just to make sure I was on paper before I went out to 100yd. Granted I am no great shooter I can do ok in holding a ok group with my other guns.....The trigger sucks on this one I will be fixing it this week. It seems that most people are thinking that it is int he scope I just having a hard time buying this.

scythefwd
September 20, 2011, 07:58 PM
Parallax should cause off center group, not scatter.

If you break cheek weld between each shot AND have an inconsistent head position when you re-aquire your cheek weld.. parallax can have you all over the paper.

scythefwd
September 20, 2011, 08:14 PM
physics dont allow for a one hole group at 50 and 5" of expansion in the next 50y. that expansion pattern for the rounds would look like a funnel with a large mouth instead og the cone that is actually physically possible.

if the group is 5 shots, all touching .... the largest group can olny be 1.115 at 50y. add in sighting errors of 2 inches (huge allowance for error here) and your groups are still <5" at 100y. there is shooter error involved.

is this your first centerfire rifle or first non intermediate cartridge rifle? what types of groups do you get with factory ammo? if you havent shot it with factory ammo..... do so and get a baseline that eliminates the reloads.

where are you located? maybe a local member is willing to go to the range and help out.

shooter errors are magnified with added distance.

have another shooter do a group.... if the pattern is still 5"... then i'll believe equipment is the problem.

biga972
September 21, 2011, 09:35 AM
I uderstand shooter error how ever with my .223 I can do ok at 100, with my 300wsm I can same hole at 100. But I do understand it still maybe me, this is a new gun for me. I will shoot some factory ammo soon.

popper
September 21, 2011, 11:23 AM
I replaced mine, helped a lot. I don't think it is your scope or load, just need to get practiced on it. Again, I recommend a good 308-AR shooter with factory ammo to check it out. That sucker really torques a lot when fired.

Clark
September 21, 2011, 01:28 PM
I should have read the OP better.

I put a benchrest 6mmPPC take off barrel on a Sav99 and re chambered to 6mmBR.

Those barrels are only 1 turn in 14" twist.

The 75 gr Vmax would do a 0.1" group at 50y, but keyhole at 100 yards.

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