Bipods and barrel vibrations

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stillquietvoice

stillquietvoice

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Just out of curiosity can the springs on the legs of a bipod cause point of impact changes by altering the point of bullet exit? Will damping the spring vibrations change poi? I ask because I hear or feel the springs when I shoot my m11 in 223 rem.

How would I go about testing this out?
 
stillquietvoice said:
Just out of curiosity can the springs on the legs of a bipod cause point of impact changes by altering the point of bullet exit? Will damping the spring vibrations change poi? I ask because I hear or feel the springs when I shoot my m11 in 223 rem.

How would I go about testing this out?
Click to expand...
No idea if it is the springs or not however the added mass of the bipod will most likely affect POI from non-bipod shots. The ONLY way to determine this is take 50 or so of your best shooting ammunition-head to the range and set up multiple targets- fire 5 or even better 10 round groups allowing the barrel to cool in between strings-compare.
That should allow you to figure out what is going on with THAT PARTICULAR rifle-I am hesitant to expand the results to other weapons as each is an entity upon itself.

Let us know.

Gary
 
I would expect, for a rifle with a free-floated barrel, that the barrel harmonics will be disconnected from the front rest (bipod or other).

I can get changes in POI relative to POA by changing how I employ a front rest (and I have proven that I can make a rifle wildly inaccurate by not controlling the rifle's behavior on the front rest!) but that's all irrespective of the behavior of the barrel itself.
 
OK so I'm still doing load development for this rifle, but I had a promising load of 25.8 gr of imr 4895 under a 55 gr hornandy sp that went into a ragged 1/2 in hole at 34 degrees. I also loaded up 26.0 and 26.2 gr. 25 of each went to range at 60 degree temperature none preformed well.

I typically shoot from front and rear bags the bipod is for field shooting after a consistent load is found.

To answer another probable cause they barrel is free floated I opened up the barrel channel enough to slip a dollar bill folded in half.

I have another bipod on another rifle that I made spring dampers for out of rubber 5/16 fuel line, but don't know if that made any difference except that I don't hear the spring twang resonating after the shot.

I'll have to try the rifle without the bipod and see if it changes
 
stillquietvoice said:
How would I go about testing this out?
Click to expand...

Shoot a group from bipod on a hard surface like concrete
Shoot a group from a soft surface like dirt or grass or fold your mat in half and put the bipod legs on it.
Compare groups

Try removing the rubber feet and do it again.

Remove or capture the springs with duct tape or something and try again.

I rather doubt the springs have anything to do with it.
 
LoonWulf said:
Only way I can see a bipod affecting the shot is if it's barrel mounted, or you lean so heavily on it the stock touches. Everything else would be shooter related.
Click to expand...
This is exactly what I've found.

I finished off a 5-shot 200-yard 1/2 MOA group with the last two from a bipod (first three were on sandbags), just out of curiosity. Got my answer.
 
The key to a bipod is the ability to load them up. If you can they won't hop enough to throw a shot. Just like others have said. If your on a bench its nice to have a stop to load up on.

FWIW I have been shooting off a rest too long because it gives me the best groups on the bench. But I am going to go prone with the Bipod when the ground dries up.
 
Was out at range Sunday with my grandson set up several targets between 50 and 300 yds. Set up a dirty bird 12 x 18 splatter target with 6 bulls. Before the two of us ever on a hot firing line 2 other shooters came a father and son. They set up at 50 and 75 deer anatomy targets. Son was shooting 308 win while father spotted for him. I had to resign several guns but when I went to shoot my 6 bull target discovered that it had 308 holes in 4 of the bulls. I was irritated to say the least but shot on them amyway. Here is my last 8 shots at 100 using red red box value pack 55 gr fmj. The holes in 8 and 9 ring ate 308 not mine.


I dont get how it stacks bullets like this then shoots 2 moa. IMG_20190415_202133.jpg
 
Wreck-n-Crew said:
FWIW I have been shooting off a rest too long because it gives me the best groups on the bench. But I am going to go prone with the Bipod when the ground dries up.
Click to expand...

Me too. Shot the centerfire challenge this weekend with my .308 and used my Atlas for the first time in a long time. My accuracy wasn’t very good.
 
stillquietvoice said:
I dont get how it stacks bullets like this then shoots 2 moa.
Click to expand...

Honestly there is probably an easy fix for what is happening but finding the actual cause may take some perseverance. Get back to basics of checking your rig.
I'm assuming m11 Savage? Torque everything including stock mounting bolts. Don't guess, get the specs. Check for witness marks on the stock inletting for metal rub and barrel free floating when it's hot. Metal expands as it heats up. Leave nothing to chance. I bet you find it.
I had a m111 30/06 do a similar thing.
Took a while to find it but as it heated up the bolt would rub the back of the bolt cutout. Aftermarket laminated stock- the bolt cutout needed opening at the back. Problem solved.
Hope you find it.
Happy shooting!
 
How much gap is necessary for a completely free floated barrel? I just checked with 3 dollar bills rifle on fully extended bipod. They slid easily from forearm to barrel nut. IMG_20190416_085247.jpg
 
stillquietvoice said:
How much gap is necessary for a completely free floated barrel? I just checked with 3 dollar bills rifle on fully extended bipod. They slid easily from forearm to barrel nut. View attachment 836769
Click to expand...

Stack 15x $1 bills, then you’d have sufficient free float. I generally want at least 1/16” free float to ensure stock flex won’t allow contact, as well as sufficient convection for cooling.
 
Nature Boy said:
Me too. Shot the centerfire challenge this weekend with my .308 and used my Atlas for the first time in a long time. My accuracy wasn’t very good.
Click to expand...
Isn't it funny how just loading up on a bipod will change something else in your actions that show up down range? It's crazy but it takes mental thought to know your loading up right when your not use to it but it changes the way your mechanics are. It's definitely a learning process.
 
it really doesn't usually. laying prone on the ground, i can front load, rear load or neutral, and get the same POI and velocity.

there are some surfaces however, that can cause some bounce

the bipod loading i believe is from the "drive the gun" school, and really is to help control recoil so you can see your trace/impact.
 
^this.

With a good rifle, preloading is a hindrance to precision. It can be a necessary evil, in some circumstances to allow spotting through your own scope - but I’ve learned to prefer a brake and a heavy rifle if that’s the game I am playing, rather than trying to push my rifle around.
 
Never had a rifle with a brake on it. I did make it out Tuesday shot some 69 gmm. Horizontal was .3 had 1 in vertical. Still chasing.
 
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