Prone Position Semi Auto

[wigwamitus]

Trying to figure out how much improvement I can get on group size from prone with semi-auto. I've been shooting 2 guns for the past 30 days and here are the groups

7.62(20) REM700 + Bravo

Prone: 0.65 inches (26 groups)

RRS Tripod: 0.98 inches (18 groups)

==
6.5G(18)

Prone: 0.81 inches (10 groups)

RRS Tripod: 0.81 (12 groups)

==

==

There have been several issues:

01 - The bipod (a harris swivel) has come loose several times causing the rifle to move laterally during recoil. This was caused by the surface of the bottom of the "spigot" of the bravo not producing enough friction to hold the bipod tight enough. I reluctantly added an ADM mount in between and that has mitigated this issue. But I count all groups, even equipment issue groups. It is my job to spot the issues just has much as it is to pull the trigger

02 - The Scope on the grendel was too low, I was having to turn my head at 45 degree angle to get behind the scope when prone. I've reverted to my infamous "rails on rails" to get it up higher.

The groups are all 4 round groups. I use 5 groups of 4 rounds each when I shoot groups but call the first group "the sighters" ... this is to give me a chance to flush work issues from my head ... and also spot equipment issues. In practice, these first "sighter" groups are just as tight as the non-sighter groups and for 2019 I will skip the sighter groups and just fire all the groups for the record.

The trigger hand position I'm using on the grendle (which is the semi-auto in question) I call the "pinch" position. The ball of the thumb is on the upper rear of the pistol grip, the trigger finger is on the trigger. The other three fingers have their tips resting on the pistol grip. And the support arm is holding the rear bag up under the stock. This trigger position seems to work well ad most closely mimics the trigger position I use on the bolt gun with the bravo stock.

==
So the question is, is there something else I can do to improve the groups of the grendel from prone? I see some folks saying you have to "muscle" a semi-auto ... but that idea flies directly in the face of "do not muscle the gun" ... so I am not muscling ... and unless I am out of position, I'm not having the barrel "bounce" ... so I'm not 100% sure why we are supposed to muscle ... but I think it has something to do with "managing recoil" ... perhaps if I was shooting a 7.62 semi-auto, I would see this problem? But I'm not seeing it with the grendel.

Thanks !!!



(and I searched this forum for all articles with "position" in the title and found nothing addressing my issue)

 

[wigwamitus]

Ok, just went out, and for 2019 decided "new style" groups will be 2 + 3 + 3 + 3 + 3 + 3 + 3 ... i.e. 2 sighters ... and 6 - 3 rd groups (shooting at 3/4 inch dots at 100yds).
This set was 7, 8, 8, 10, 11, 24 (measured in 16ths and sorted in size order to make it easier to remember them. So today's avg was 0.71 with the 24 (1.5 inch) and 0.55 without the 24 ... I count all of them, but just for info sake I consider subsets. I was "zeroing" but only dialing after each group was complete, so the zeroing process had no effect on the group sizes. I think the issue with the 24 was poor head position. The first round was way left, the others were fine.
But this is more like it. I think these are the first groups I've fired prone since added the "rails on rails" and I think that is helping with head position. but I'm still curious if many people "muscle" their semi-autos while shooting prone. Is 0.5 MOA possible ??

 

[SnkBit]

Excellent topic. I wish I could help, but I too am having issues with semi’s.

 

[GrandpaDeadLegs]

My plan for getting better involves taking videos of myself shooting using the slo-mo function on the iPhone. Should be some painfully good self-reflection there.

I don't muscle it, more like try to keep calm until the bullet hits the target instead of keeping calm until the bullet leaves the barrel. Follow through, like they say on the podcast, is more important on the semi

 

[wigwamitus]

2018-12-28
1200-1400
20F
10 MPH WNW

Goal: Zero 6.5G(18) and check at 500yds.

Environment: Cool and windy, it rained hard 2 days ago and now everything is frozen ... frozen ground, frozen pools of water, etc. Heavy overcast.

Equipment: 6.5G(18) ELD-M 123, L&S 3-18x T3, Kestrel. Weight of gun 11 LB 12 OZ.

Activity: Fired 20rds at 100yds, avg group size .71 with one flier, without that 1 flier avg group size 0.55.

Then went to 500yds. Wind read, low 5.1 high 12.1 avg 8.5.
Wind direction based on 3 tosses of grass, 350 off the bullet path. Held for 2 mph left. And shooter said 3.9 up. Fired 5 rds, got 5 dings on the steel, I could hear the wind pick up, but I could see I was still on target. Group size 5.25 inches. Just a tiny bit over 1 moa (5.235).

I did wind up pulling back towards my shoulder a little with the pistol grip. I could notice a little "bounce" ... pulling back seemed to help. I will try that at 100yds and see the effect on the groups.

 

[wigwamitus]

2018-12-29
1300-1430
20F
0-10 MPH S - W

Goals: Wind practice

Environment: Clearing, sunny, cool, ground frozen, no wind in some spots, wind in other spots. Pic of our wind mill as I rode out (and as I rode back) no wind in this spot. The turbine is facing SSW.

Equipment: 6.5(18) L&S Mk6 3-18x T3 ELD-M 123, 2 5rd mags, 4 wheeler

Activity: Rolled out to alfalfa patch and handed out some range cubes ... noted our #8 mom had a calf last night. That is our 10th of the season, still 4 more to go!

Then rolled up to hill 1309 (so named as the summit is 1309 FASL) and setup. I had no range finder, so I guessed I was at 725yds.

Shooter said up 7.4 MILs. At 18x the 7.4 mil hold was pretty low down in the scope, so cranked down to 15x to raise up the spot the hold was in.

I threw 2 tufts of grass up and noted the wind direction was from the West and so I held for 2 MPH left and 7.4 up. I saw the dirt splash of the miss at 2 wind dots right.
Second shot I held two wind dots left and 7.4 up and the round hit dead center just below the target and a piece of bullet struck the target on the bounce (high center darker smudge on the target).

So, I was low, so for the rest of the shots I held 7.8 mils which means I was really at 740 yds.

3rd thru 10th rounds pinged the metal.
Painting the targets grey certainly makes them harder to see

I had no rear bag either.

Went to check the target, decided to cross the creek on foot instead of driving around the long way ... the creek was deep enough I had to cross at a shallow spot and work my way down the frozen rocky bank.

I use roots to hold on to. Crossed fence and then was in our NE brome patch where the target is. Went to target and took pic, then returned via same path.

For my official wind practice, I think I will score this 2.5 points. And first round hit is 10 points and second round hit is 5 points. A second round ricochete hit will be 2.5 points

Hits 3-10 do not count for official wind practice scoring. Only hits from the first 2 rounds count.