M118LR is tight in the chamber of my GAP

[Hookman]

I had some issues with M118LR(05)and I can use your guidance and expertise here..I went to the range to see how my GAP SCLE would shoot with it and I noticed right away it was tight in the chamber and I had to put some muscle into closing the bolt. I shot several rounds, all with a hard bolt closure but with excellent groups. It was apparent the chamber on my GAP is tight when I cycled one round without firing and when I opened the bolt, the bullet was stuck on the lands of the rifle and I pulled the case off the bullet spilling powder all over my action.

Has anyone else experienced this before with M118LR out of a GAP SCLE (Rock)?

I came home and measured the chamber and ogave with a OAL gauge and comparator of my GAP and the loaded M118LR and this is what I came up with. (if my measurements are correct)

175 SMK's in my GAP are on the lands at an average of 3.204
M118LR is avg. of 3.241 at the ogave

So it seems like I am .039 into the lands with the M18LR ammo.

I am thinking I re-seat the bullets further into the case so that I am off the lands but I don't know if that would cause any complications?

Thanks ~ Hookman

 

[sinister]

Re: M118LR is tight in the chamber of my GAP

Sounds like your rifle is chambered for 168s.

 

[Niles Coyote]

Re: M118LR is tight in the chamber of my GAP

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hookman</div><div class="ubbcode-body">I am thinking I re-seat the bullets further into the case so that I am off the lands but I don't know if that would cause any complications? </div></div>

I have bumped them back enough to break the sealant and had no issues.

 

[m1match]

Re: M118LR is tight in the chamber of my GAP

I've got a GAP SCLE and shooting 175 MKs loaded to 2.80 OAL I've had no such issues. Pulling a bullet out of the case definitely means that your bullets are seating hard into the lands. When GA Precision did the SCLE run of rifles, they were chambered to shoot 175 Match Kings loaded to 2.80 OAL.

Here's what George Gardner said when he posted the specs of the rifle build on Sniper Country:

"Caliber: 308 Win, Will Use a special PTG Reamer set up for 175's at 2.800 OAL. Reloaders and factory amunition buyers will both like it. "

Your length measurements are using a comparator which may or may not directly relate to another comparator. Using a 1998 vintage Stoney Point Comparator, the dial caliper reading on my 175 MK reloads loaded to 2.80" overall length was about 3.222" and they are not into the lands in my SCLE rifle.

Why don't you email GA Precision and see what they say?

 

[Hookman]

Re: M118LR is tight in the chamber of my GAP

Thanks for the info guys! I will first send GA Precision an email and see what they have to say about the chamber specs and what specs to load my ammo to, then I decide to seat the bullets deeper on the 118LR ammo, or just save them for another rifle.

Hookman

 

[Hummer]

Re: M118LR is tight in the chamber of my GAP

You have a shorter throat which is good. Your barrel will last longer. I have a reamer I have to set back 30.06 match .065" to get it to close.
It takes about 500 rounds to wear it in for me.
Your new cases should measure .468 measured .200" up from rim. What do your fired cases measure?

Also measure unfired and fired necks. What do they measure?

 

[m1match]

Re: M118LR is tight in the chamber of my GAP

Even if his cases are oversized and part of the cause of hard bolt closing, his bullets are seating hard into the lands or else he wouldn't have unchambered a round pulling the case from the bullet and leaving the bullet still stuck in the rifling.

 

[Hookman]

Re: M118LR is tight in the chamber of my GAP

Hey guys, I contacted GA Precision about this issue and received a response from Karey Bruner. He said that the chambers on the SCLE's were all cut with a 95 Palma reamer and they went away from that reamer for the exact reason I mentioned above.

 

[m1match]

Re: M118LR is tight in the chamber of my GAP

Thanks for letting us know what GA's answer was Hookman. You got me intrigued, so I measured my SCLE rifle using 175 SMKs, a Stoney Point OAL gauge, and a Stoney Point Comparator and in my rifle which was #43 of the 50 made, the cartridge length to the throat was 3.225", or .021 longer than your rifle. Measuring my 175 SMK reloads seated to 2.80" OAL, the comparator measurement was 3.215, or .010" off the lands.

 

[Hookman]

Re: M118LR is tight in the chamber of my GAP

you're welcome, m1match. I think the 118LR's are loaded with a longer OAL. I don't know why there is a difference in the chambers of our rifle. BTW Mine is #32 of 50.

I am relatively new to reloading but I believe I measured it correctly. I am going to re-seat the 118LR to OAL of 2.800 and they should load and fire through my rifle without any issues.

 

[m1match]

Re: M118LR is tight in the chamber of my GAP

What is the overall length base to tip of bullet of your M118LR? If its much longer it wouldn't work in M14 mags. Keep in mind, when I say 2.80" I mean that base to tip of bullet measurement, which isn't comparable to the measurements we're taking with a comparator measuring the bullet ogive. If I wanted a base to bullet ogive measurement, I would need to measure how long the Stoney Point Comparator tool is then subtract that measurement from the 3.215" I measured, that would give me the base to bullet ogive measurement, then to relate that to where the throat is, I'd need to do that same subtraction from the measurement using the Stoney Point OAL tool.

 

[Hookman]

Re: M118LR is tight in the chamber of my GAP

The 118LR measures 2.814 on avg. from tip to base and they fit in my M1A mags without a problem. I also shot them out of my FN SPR last weekend without any issues. So it appears the SCLE chamber is the issue since its cut with a 95 Palma reamer.

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[9H_Cracka]

Re: M118LR is tight in the chamber of my GAP

Those dimensions scream it was chambered with a 95 Palma reamer (.050" freebore) rather than a 175 Match reamer (.100" freebore) or M852 reamer (.120" freebore with a larger ID straight section).

 

[XTR]

Re: M118LR is tight in the chamber of my GAP

I've got a bunch of LC M80 here and it all runs about 2.79 - 2.80. sounds like a really short chamber.