Author Topic: Minor issue with my .17HMR Sportster, probably worrying over nothing....  (Read 769 times)

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Offline MacTech

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Ever since I bought my Sportster, I've noticed that it has no problem ejecting live rounds rather *enthusiastically*, like all ejector-model H&Rs, but when I fire a round and go to break it open, it acts more like an ejector, it doesn't kick the cartridge out more than a couple inches, sometimes it will push it out and have it drop halfheartedly to the table, but it's not tossing them far like it does with unfired rounds

My first thought was the infamous "split brass" problem, but any fired shells I looked at looked fine, no signs of splits, nothing, the fired brass looks absolutely fine, I can put the fired shell back in to use as a snap-cap, and after firing, there's a 50/50 chance of it even ejecting, it usually takes a tiny bit of prying with the mini-eyeglass screwdriver that fits in the corkscrew of a SAK to coax the shell out far enough for the ejector to "extract" it

this is a brand new rifle, about 125 rounds through it so far, and is amazingly accurate (one-holers at 50Y without even trying), this is really the only issue I have with it

So, tonight, I noticed, when compared against fired brass, my unfired cartridges neck area seemed to go back further and the bottleneck part was less pronounced, on a fired cartridge, the neck got shorter and the bottleneck rounded out more, basically the "shoulders" got broader and the "neck" got shorter

Breaking out my micrometer, I get the following measurements;

Unfired round;
1.050 OAL (not counting bullet)
0.035 width above rim
0.035 width before bottleneck
0.187 width just before bullet
0.129 neck length
0.073 shoulder length

and this on a fired case;
1.060 OAL (.010 longer)
0.040 width above rim (.005 wider)
0.035 width before bottleneck (unchanged)
0.187 width just before bullet (unchanged)
0.111 neck length (.018 shorter)
0.067 shoulder length (.006 shorter)

I know all brass will fire-form to fit the chamber it's being fired in, and some dimensional change is normal, I'm just wondering if my HMR's chamber is within spec, loose, tight, what?

to reiterate, however, the gun has been 100% reliable so far in all aspects of chambering, firing, and extract/ejecting, it's just not as...."enthusiastic" as my old .22LR Sportster at kicking the empties out....

According to the Lija barrels website, one of the "side effects" of a tight/match chambered barrel may be a difficulty in ejecting unfired or fired rounds, I love the accuracy of my HMR, if I have to give up a little bit of that fun "enthusiastic" ejector action, so be it, accuracy is more important to me, and the fired shells *do* eject, just not all the way, in fact, it's like the ejector is a hybrid of an extractor and ejector, it pushes the cartridge out further than an extractor, but doesn't send it into the next zip code like an ejector, makes clean up at the bench a cinch :)

I think what's happening here, and I may be wrong, is when the gun is fired, the brass case fire-forms to fit the front of the chamber, the shoulders round over slightly and it ends up "sticking" in the chamber a tad more than required, since it's fire-formed to fit the chamber, when the ejector goes to toss the empty, the extra drag from the fireformed section slows it enough to cause it to not get completely flung out

Offline quickdtoo

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Re: Minor issue with my .17HMR Sportster, probably worrying over nothing....
« Reply #1 on: January 16, 2011, 01:26:25 PM »
You have a few choices, perform the ejector tune and/or polish the chamber, both are in the FAQs sticky,  or follow the directions on the repair page of H&R's website and make arrangements to send it to H&R for repair, call and ask them to send you a prepaid shipping return label to cover cost, repairs are usually returned in less than a month. That's a good time to get a trigger job done also(FAQs again).

Tim

http://www.hr1871.com/support/repairs.asp
"Always do right, this will gratify some and astonish the rest" -  Mark Twain

Offline MacTech

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Re: Minor issue with my .17HMR Sportster, probably worrying over nothing....
« Reply #2 on: January 16, 2011, 03:29:32 PM »
I think you're right about the chamber polishing, on a whim, I took a fired case that ejected slowly, and wiped a thin layer of CLP on it, re-inserted it, closed the action, opened it and the empty was spit out quite enthusiastically, looks like a polish job should "Git 'er Done" ;)

Offline gcrank1

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Re: Minor issue with my .17HMR Sportster, probably worrying over nothing....
« Reply #3 on: January 16, 2011, 05:41:29 PM »
Dont get overly enthusiastic in 'polishing'. Per C.E. Harris the chamber is the key to accuracy in rimfires, and it sounds like you have a winner. Maybe do the BB trick, etc. in the FAQs first and see how that works. If you 'need' to polish proceed with caution.
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