Heavy bolt lift with suppressor

[stello1001]

Hey guys,

Went to the deer lease last week to sight a rifle I gifted my dad. I've had trouble with this rifle since forever. Anyhow, specs are below:

Howa mini
6.5 grendel
Original barrel cut to 18" and threaded by smith
Boyds Pro Varmint stock pillar bedded by Smith
TBAC Dominus

Ammo was Hornady Black 123 ELDM

I started shooting and sighting without suppressor and even tried a different factory load to see what the rifle liked best. I got a good feel for bolt lift during all this.

When I settled on the 123 ELDM because it shot better, I decided to shoot a group with suppressor and threw it on. Not only did the POI shift a little which I know is normal, the group opened up, and I had significantly heavier bolt lift on most rounds fired. All rounds fired that did have heavy bolt lift were with suppressor on.

I inspected cases but saw no clear marks on them other than a few I could just barely tell the ejector printed on there ever so slightly.

Anyone care to give me any advice? I'm definitely less experienced than most on here and couldn't come up with a reason why this is.

Thanks

 

[kthomas]

A very hot load that may not show obvious signs of pressure can start to show those signs with the introduction of a suppressor.

The ammo is too hot for the gun.

 

[stello1001]

Damn this sucks, this could probably explain the accuracy issues as well.

 

[kthomas]

Damn this sucks, this could probably explain the accuracy issues as well.

You say you've had issues with this rifle "forever" - what are those issues?

And you are using factory ammo, correct?

 

[stello1001]

You say you've had issues with this rifle "forever" - what are those issues?

And you are using factory ammo, correct?

The rifle had no consistent accuracy when I first got it. It was all over the place.

I leave for work and am never home. Finally, I got back recently and decided to take it apart.

There was some bedding compound in front of the recoil lug making contact with the barrel. I sanded that off and assembled it back together with 50in/lbs on both action screws.

I can't say for sure what was the culprit but at least now I am getting consistency.

I wrote up a range report not too long ago on its but forgot to ask about the suppressor issue, hence why I made this thread.

**edit**

Here are the results


I went out today after removing the little spot of bedding material contacting the barrel and putting her back together.

I set up where I thought would be close enough to borescope and just get on paper. After ranging, that turned out to be 77 yards. I said fuck it and rolled with the punches.

First shot was very high and left. My aiming point was the middle of the 3 orange boxes on the bottom. First shot is not labeled but is visible on picture.

I made one correction basing of the POI using my reticle. Aimed back at the same target and voila! I got the impact inside the orange square just on the bottom. Second shot was just outside to the left and third on the top right quadrant.

Since this is a hunting gun for my dad, I didn't care about having a rifle that shoots 1/3 moa. After all, he will be shooting deer inside 200 yards.

I decided to try Federal 90 grain TNT just to get to know the rifle better and see if it prefers one ammo over another. I didn't like the group.

Next up was going back to the original ammo tested, which is hornady black loaded with a 123 ELDM. Aiming point was top left blue square with the thick bold outline. Group definitely opened up and suppressor shifted the POI. Wasn't really too happy. Suppressor is a TBAC Domius.

I brought out my FN SPR to see if I could eliminate myself as the culprit. I shot the top right blue square and had the 3 impacts just low of my aiming point. I made one correction and I was good with the result. I shot my FN SPR with the suppressor both times using Norma ammo loaded with a 175 grain golden target.

At this point, this is a huge improvement over last time I took the rifle out. However, I Shot steel out to 300 yards and could never get any consistency on a 8.5" plate. I made first shot impact almost dead center using the suppressor (which at this point is already cool to the touch) and guesstimated a 1.4 mil solution. I let dad rip a few more since I was already on target. He missed both. So now I get back on the rifle to see if it's him or the rifle. I wasn't able to figure it out. I held over and under many times as well as dead center. I tried with and without suppressor.

At this point I'm a bit frustrated so I get the 308 out to see what's up. I guesstimate again a 1.1 mil solution and sure enough I get consistent hits, my dad gets hits, and a guest we had also had consistent hits. He even had a blast shooting the SPR.

I guess we're back to square one at this point. I'm not comfortable letting my dad hunt with this rifle yet. If you've read this far on my range report, congrats lol!

TLDR:

Rifle shot decent with hornady black 123ELDM at 77 yards without the suppressor. Shot like crap with or without suppressor at 300 yards.

 

[kthomas]

If you have time, do this:

- Take a round of loaded ammo, and scuff up the bullet with steel wool.
- Insert the round into the chamber and close the bolt.
- Extract the round very carefully, and have a look on the bullet to see if there is any markings from the lands on the bullet.

Perhaps you have a really short freebore. Or maybe the reamer they used was worn out, causing pressure issues or heavy bolt lift. I have a feeling something is up with the chamber if you are having pressure issues with factory ammo.

I should also ask - is pressure observed with other factory ammo? Are any pressure signs showing on the base of the brass or primer? Or is the only sign a heavy bolt lift?

I will also tag in an expert like @LongRifles Inc. to see if they have any idea as to what's going on.

 

[kthomas]

I should also ask - is there any indications of a tight fit with the ammo when you insert a round and close the bolt? I.e. is the bolt close pretty stiff on a loaded round?

Can a fired piece of brass be inserted into the chamber?

 

[stello1001]

If you have time, do this:

- Take a round of loaded ammo, and scuff up the bullet with steel wool.
- Insert the round into the chamber and close the bolt.
- Extract the round very carefully, and have a look on the bullet to see if there is any markings from the lands on the bullet.

Perhaps you have a really short freebore. Or maybe the reamer they used was worn out, causing pressure issues or heavy bolt lift. I have a feeling something is up with the chamber if you are having pressure issues with factory ammo.

I should also ask - is pressure observed with other factory ammo? Are any pressure signs showing on the base of the brass or primer? Or is the only sign a heavy bolt lift?

I will also tag in an expert like @LongRifles Inc. to see if they have any idea as to what's going on.

I will try seeing if my bullet is into the lands. I suppose I can also try with a sharpie by coating the bullet with it and looking for land marks if I do not find steel wool around the house.

Although, i dont think thats going to be my issue. I have never noticed a tight fit with ammo but i suppose i wasnt exactly looking for or trying to notice this before.

The only time i felt or noticed something wrong was when i fired with the suppressor i got excessive heavy bolt lift. This to me is an indication of pressure and i inspected the case head but only found ejector prints but extremely faintly. You almost can not see it.

I have Federal loaded ammo with a 90 grain TNT bullet. I only did one 3 round group and it had lots of vertical dispersion which was enough for me to discount the ammo and not consider it any further.

That is what my testing consisted of. The factory loaded ammo by hornady with a 123 ELDM & the Federal with a 90 TNT.

I also now bought some more factory Hornady but this is loaded with a 123 BTHP.

I will try with all 3 inspecting for land marks and i will test fit brass from the 2 different factory ammo i shot already and see if there is a tight fit.

I should also ask - is there any indications of a tight fit with the ammo when you insert a round and close the bolt? I.e. is the bolt close pretty stiff on a loaded round?

Can a fired piece of brass be inserted into the chamber?

Thanks for your suggestions, I'll report back with my findings soon.

 

[stello1001]

Ok, so here it goes...

All 3 factory loadings that I have on hand load into the gun and chamber almost identical. That is, I push the round forward into the chamber with the bolt and when I try to close down the bolt, it's hard. It's hard because it seems as if the ammo is long because once I push the bolt forward into the chamber, it moves a slight bit forward then I am able to come down very smoothly and with ease. This is with all 3 loadings that I currently have.

Hornady Black 123 ELDM
Hornady black 123 BTHP
Federal American Eagle 90 TNT

Ok, now that that's outta the way...
I loaded one of each with a bullet coated with black sharpie. The two Hornady loadings appear to maybe be just barely jamming into the lands. You guys be the judge.

If that is indeed a land mark, there is only one land (or just one marking) making contact with the bullet, not multiple.

Now let's move on to fired pieces of brass...
The two loadings that I've fired are 123 ELDM & 90 TNT. Both types feel significantly heavy or difficult I should say to chamber. I still get the same feeling as if the brass is long so I have to really push the bolt forward after it "stops" in order to lock it down. Only difference is, with loaded ammo, coming down is easy. On fired brass, coming down takes considerable force.

Another observation I made on the fired brass pieces, some have a weird mark on the neck/shoulder junction. This includes both federal and hornady brass.

This is a federal brass but the same mark can be found on a few Hornady pieces. This is not on all fired pieces but only a few.

Another observation I made...
On the fired brass pieces, since it takes considerable force to chamber, I decided to try something. I tried chambering the brass multiple times in an attempt to see if I could get anything to mark or imprint itself on the brass. Sure enough, it seems there is one area where brass is being "scratched" maybe??

We can see on the above pic a mark that appears only after chambering the brass many times.

So after all, I'm guessing there is a shitty chamber job on this rifle. The chamber might be too short and possibly the throat too??

 

[FuhQ]

Hey guys,

Went to the deer lease last week to sight a rifle I gifted my dad. I've had trouble with this rifle since forever. Anyhow, specs are below:

Howa mini
6.5 grendel
Original barrel cut to 18" and threaded by smith
Boyds Pro Varmint stock pillar bedded by Smith
TBAC Dominus

Ammo was Hornady Black 123 ELDM

I started shooting and sighting without suppressor and even tried a different factory load to see what the rifle liked best. I got a good feel for bolt lift during all this.

When I settled on the 123 ELDM because it shot better, I decided to shoot a group with suppressor and threw it on. Not only did the POI shift a little which I know is normal, the group opened up, and I had significantly heavier bolt lift on most rounds fired. All rounds fired that did have heavy bolt lift were with suppressor on.

I inspected cases but saw no clear marks on them other than a few I could just barely tell the ejector printed on there ever so slightly.

Anyone care to give me any advice? I'm definitely less experienced than most on here and couldn't come up with a reason why this is.

Thanks

Your accuracy issues are because you’re using shit factory ammo. Hornady Black has never shot good in any of my 6.5G’s or 6 ARC. You’re pressure issues are because introduction of a suppressor increases chamber pressures because it catches and constricts gas at the end of the barrel creating higher pressures inside the bore and chamber than it does without the suppressor.

Solution is simple… Work up a handload with the rifle WITH the suppressor on it. See what shoots best, roll with that.

 

[PCR]

The picture of the fired case with the obvious inclusion could very possibly be from a rolled chip in the chamber and explain a why only one side of the bullet with black marker is scuffed. Also giving you resistance when closing the bolt and again, possibly accuracy issues

 

[kthomas]

The picture of the fired case with the obvious inclusion could very possibly be from a rolled chip in the chamber and explain a why only one side of the bullet with black marker is scuffed. Also giving you resistance when closing the bolt and again, possibly accuracy issues

Yeah, I think there's something going on with the chamber that warrants further investigation...

 

[B'N'F]

Ok, so here it goes...

All 3 factory loadings that I have on hand load into the gun and chamber almost identical. That is, I push the round forward into the chamber with the bolt and when I try to close down the bolt, it's hard. It's hard because it seems as if the ammo is long because once I push the bolt forward into the chamber, it moves a slight bit forward then I am able to come down very smoothly and with ease. This is with all 3 loadings that I currently have.

Hornady Black 123 ELDM
Hornady black 123 BTHP
Federal American Eagle 90 TNT

Ok, now that that's outta the way...
I loaded one of each with a bullet coated with black sharpie. The two Hornady loadings appear to maybe be just barely jamming into the lands. You guys be the judge.

View attachment 8241079View attachment 8241080View attachment 8241081

If that is indeed a land mark, there is only one land (or just one marking) making contact with the bullet, not multiple.

Now let's move on to fired pieces of brass...
The two loadings that I've fired are 123 ELDM & 90 TNT. Both types feel significantly heavy or difficult I should say to chamber. I still get the same feeling as if the brass is long so I have to really push the bolt forward after it "stops" in order to lock it down. Only difference is, with loaded ammo, coming down is easy. On fired brass, coming down takes considerable force.

Another observation I made on the fired brass pieces, some have a weird mark on the neck/shoulder junction. This includes both federal and hornady brass.

View attachment 8241082View attachment 8241083

This is a federal brass but the same mark can be found on a few Hornady pieces. This is not on all fired pieces but only a few.

Another observation I made...
On the fired brass pieces, since it takes considerable force to chamber, I decided to try something. I tried chambering the brass multiple times in an attempt to see if I could get anything to mark or imprint itself on the brass. Sure enough, it seems there is one area where brass is being "scratched" maybe??

View attachment 8241084
We can see on the above pic a mark that appears only after chambering the brass many times.

So after all, I'm guessing there is a shitty chamber job on this rifle. The chamber might be too short and possibly the throat too??

If the barrel came this way from Howa, they'll be using either a SAAMI or CIP reamer, so the likelihood of a short throat is fairly minimal, but the "frosting" on the brass as shown in your last picture indicates the brass is sticking in that location. Likewise, the 'crease' or deformation of the brass at the shoulder is definitely indicative of something greater going on - fired brass definitely shouldn't be looking like that coming out of a bolt gun.

It's hard to tell if it's a reflection from your table cloth, but is there gas wash, or signs that gas has been deposited on the brass in the location of that creasing?

 

[stello1001]

If the barrel came this way from Howa, they'll be using either a SAAMI or CIP reamer, so the likelihood of a short throat is fairly minimal, but the "frosting" on the brass as shown in your last picture indicates the brass is sticking in that location. Likewise, the 'crease' or deformation of the brass at the shoulder is definitely indicative of something greater going on - fired brass definitely shouldn't be looking like that coming out of a bolt gun.

It's hard to tell if it's a reflection from your table cloth, but is there gas wash, or signs that gas has been deposited on the brass in the location of that creasing?

The barrel did not come this way from factory. I made the purchase online and had it shipped to my gunsmith who is obviously also an FFL. When it was there, I had him chop 2 inches off and re-thread. Because the action is so little, it did not fit into whatever machinery (I don't know much about gunsmithing or gunsmithing equipment) so he ended up removing the barrel to do the work and re-install.

I have taken a closer look at the brass pieces with the indentation and there does not appear to be any gas deposits or signs of that going on. It looks just as shiny as the rest of the brass so possibly what you are seeing is simply reflection or bad picture quality from my phone.

 

[kthomas]

The barrel did not come this way from factory. I made the purchase online and had it shipped to my gunsmith who is obviously also an FFL. When it was there, I had him chop 2 inches off and re-thread. Because the action is so little, it did not fit into whatever machinery (I don't know much about gunsmithing or gunsmithing equipment) so he ended up removing the barrel to do the work and re-install.

I have taken a closer look at the brass pieces with the indentation and there does not appear to be any gas deposits or signs of that going on. It looks just as shiny as the rest of the brass so possibly what you are seeing is simply reflection or bad picture quality from my phone.

Your gunsmith didn't touch the chamber though, right?

It sounds like he only cut off 2" and threaded the end of the barrel - is this correct?

 

[2/319th]

Take the dented brass with the gun, to your smith and ask him what is going on. Something is in the chamber that is not supposed to be there.

 

[stello1001]

Your gunsmith didn't touch the chamber though, right?

It sounds like he only cut off 2" and threaded the end of the barrel - is this correct?

Absolutely not. But perhaps there is a possibility a metal shaving from cutting the threads made its way into the bore and onto the chamber where it hung around for a bit.

It was only in there temporarily because it's less than 10 pieces of brass that have that dent. I've gone through all the brass and most of it is fine.

 

[stello1001]

Take the dented brass with the gun, to your smith and ask him what is going on. Something is in the chamber that is not supposed to be there.

Yup, it's looking like he might need to check it out for me.


Oh and before I forget, because I'm still curious, does anyone think those marks on the sharpie bullets are from the lands touching the bullet?

 

[kthomas]

Absolutely not. But perhaps there is a possibility a metal shaving from cutting the threads made its way into the bore and onto the chamber where it hung around for a bit.

It was only in there temporarily because it's less than 10 pieces of brass that have that dent. I've gone through all the brass and most of it is fine.

Maybe.

The fact that you've had issues with this rifle since you got it makes me think that Howa did not properly cut that chamber. Or something else happened.

Not too far fetched to think that Howa cut your chamber with a dull reamer or something to that effect.

 

[stello1001]

Maybe.

The fact that you've had issues with this rifle since you got it makes me think that Howa did not properly cut that chamber. Or something else happened.

Not too far fetched to think that Howa cut your chamber with a dull reamer or something to that effect.

It's also a possibility it came shitty from the factory. But at first it wasn't grouping at all. The best 3 shot group I had was about 3 inches and I was not able to repeat it. Everything else was going everywhere with no direction.

At least now I'm grouping and there is at least some consistency so either I had it put together wrong the first time or me removing the bedding material touching the barrel helped.

 

[spife7980]

Oh and before I forget, because I'm still curious, does anyone think those marks on the sharpie bullets are from the lands touching the bullet?

If it’s that wide and only that one spot most likely it’s rubbing there when it’s extracted and the ejectors spring pressure pushing it to slide against the chamber and action on the way out is where the mark is from. Remove the ejector and test to confirm.

 

[stevieb92]

Maybe I missed it, but did you put a borescope (e.g. Teslong) into the chamber to look at it? Seems to me, this would be a perfect use for one...