This action was tried in the court below on the theory alleged in the complaint that the damage to plaintiff was caused by the breach of an implied warranty in the sale of certain 12-gauge scatter load gun shells, sold by defendants to plaintiffs. The defendants made no motion in the court below for judgment as in case of nonsuit. C. S., 567. Jones v. Ins. Co., ante, 559. This theory was recognized in the charge of the court below: “If you find from the evidence in the case, and by its greater weight, the burden of proof being upon the plaintiff Thomas W. Keith to so satisfy you, that the gun shells sold by the defendants to the plaintiff on 24 December, 1934, were not reasonably fit and proper for the purpose for which the gun shells were sold and purchased, and that by reason of any such unfitness or defect a gun shell purchased by the plaintiff from the defendants exploded in the left barrel of plaintiff’s gun on Christmas day, 1934, when the plaintiff was hunting quail, blowing out part of the left barrel of plaintiff’s gun, was the direct proximate cause of plaintiff’s injuries, it will be your duty to answer the first issue in this case ‘Yes’; if you fail to so find, it will be your duty to answer the first issue in this case No.’ ”

In Thomason v. Ballard & Ballard Co., 208 N. C., 1 (4), Connor, J., for the Court, says: “There are decisions in this jurisdiction to the effect that as between a vendor and his vendee there is an implied warranty that the personal property sold by the vendor and purchased by his vendee was fit for the use for which it was sold and purchased, and that the vendor is liable to his vendee for a breach of this warranty. Swift v. Aydlett, 192 N. C., 330, 135 S. E., 141; Poovey v. Sugar Co., 191 N. C., 722, 133 S. E., 12; Swift v. Etheridge, 190 N. C., 162, 129 S. E., 453.” Tomlinson v. Morgan, 166 N. C., 557; Ward v. Sea Food Co., 171 N. C., 33; Corum v. Tob. Co., 205 N. C., 213. “An appeal ex necessitate follows the theory of the trial.” In re Parker, 209 N. C., 693 *804(697). The trial theory of the case is controlling on appeal. Mercer v. Williams, ante, 456 (458).

Tbe matter of implied warranty is treated in tbe briefs of tbe litigants, and tbe case was tried on this theory in tbe court below. Tbe defendants’ contentions will not now be considered on this record — that in no event could plaintiff recover.

Tbe plaintiff alleged that tbe damage to him was caused by a breach of an implied warranty in tbe sale of certain 12-gauge scatter load gun shells; that one, when shot by him, bursted tbe gun and caused serious injury to bis left band and thumb. Tbe defendants in answer say: “It is admitted that tbe plaintiff’s gun exploded, and that bis left thumb and hand were hurt, and that be suffered pain and some expense for medical attention, etc. It is particularly denied that this occurred from any negligence on tbe part of tbe defendants, or any breach of warranty, and in connection therewith tbe defendants allege that they are informed, believe, and allege that either tbe plaintiff’s gun was defective or that tbe plaintiff was negligent in getting some obstruction in said gun, and in shooting tbe same with an obstruction in it.”

The facts: Tbe plaintiff bought tbe shells on 24 December, 1934, from defendants, and on tbe next day (Christmas) be and bis friend, W. P. Emerson, went bunting. .He testified: “When we got up to where we were going to park (Currie) and Mr. Emerson took my gun out of this case here while I got my shells out and got my coat on, and I broke the gun open and put two of these shells in my gun. . . . We walked on behind tbe dogs, I should say 300 yards from where we got out of tbe car, and tbe dog pointed. . . . Mr. Emerson was to my left, and I was on tbe right. I shot tbe right barrel and it made a terrific explosion, it was unusually heavy, and I shot tbe left barrel and it blew this piece of shell through my band and blew my arm away from tbe gun. . . . I cleaned it and tbe barrel was as bright as a new silver dollar. I examined it to see its condition and found no defects whatever. . . . Mr. Emerson was shooting a Remington automatic gun, 20-gauge, I think it is. I bad seen bis gun, and be told me be was shooting those Nitro Club scatter load shells, loaded with No. 8, manufactured and put up by tbe Remington Arms Company. ... I was opening my box of shells and getting on my bunting coat and putting some shells in my bunting coat while Mr. Emerson was getting my gun out of tbe ease.” On recall, be testified: “Mr. Emerson got tbe gun out of tbe case while I was putting some shells in my pockets. After Mr. Emerson banded me tbe gun and before I put tbe shell in it, I opened, or unbreached it, held it up to tbe light and looked through it through force of habit to see that there was nothing in tbe barrel, and there was nothing in tbe barrel.”

*805W. P. Emerson testified in corroboration of plaintiff, as to bis going bunting with bim and as to tbe explosion, and on cross-examination testified: “When we got up there be was putting tbis box of shells out and opening it and be broke tbe seal, and was putting tbe shells in bis bunting coat pocket. I took bis gun out of tbe case and was looking at it. I am under tbe impression that I broke it, but I cannot say definitely. ... I don’t remember when I loaded my gun. I did not drive up there with it loaded. After we stopped, while be was getting bis coat on and putting shells in it, I was getting out tbe gun. I loaded mine some time about that time as we started off. I was shooting 20-gauge Bemington Nitro scatter load shells.”

Tbe defendants offered in evidence W. T. Ashcroft, superintendent of tbe loading department of tbe Eemington Arms Company, who testified, in detail, tbe precautions that are taken in loading these shells, that it was impossible to overload one, that if an overcharge of powder should get in a shell tbe machine would stop, etc.

W. A. King testified for defendants: “I am employed by tbe Parker Gun Company, in tbe manufacture of Parker guns. I have been with tbe Parker Gun Company over 46 years. I am supervisor of quality, responsible for tbe proper manufacture and quality of tbe guns manufactured. I first learned tbe mechanical trade, was tool maker, and took up die sinking, and was placed in charge of forging of all parts; then I was placed in charge of tbe machining of all parts; in 1912 I was made assistant superintendent, and in 1914 superintendent, and a few years after that works manager, in charge of tbe entire plant. In my work I have made guns and tbe different parts, and have tested them. I have made all parts that go into a gun, or had them made under my immediate supervision.” Tbe court below held King was an expert on shotguns. “At tbe request of Gregg Brothers, I came down here previous to tbis and made an inspection of tbis gun of Mr. Keith’s, in tbe presence of Mr. Keith, and of me and of Judge Williams and Judge Bryan, in Mr. Wright’s office. Tbis is tbe same gun that I then inspected. Q. From your experience, state what you see there from your observation of that burst that indicates anything about tbe cause of tbe burst. Ans.: A distinct swell, or ring, running around tbe barrel (which tbe witness points out to tbe jury). There is evidence of foreign material. I have got a glass, and in looking at it I see it is brass. It is right here on tbe break; that is a difference in color; it is yellow. (Witness points it out to tbe jury.) Q. From tbe evidence of that you see there, and have just shown there on that gun, what, in your opinion, was tbe cause of tbe gun bursting? (Judge Bryan: Objection to tbe form of tbe question. Court: Sustained, but if you will ask what, in bis opinion, caused it, I will permit it.) Q. Please state, in your opinion, what caused that gun *806barrel to burst. A. Tbe presence of a twenty-gauge loaded shell in the barrel, and a twelve-gauge loaded shell placed in back of it and fired and the twenty-gauge shell exploding at the same moment the twelve-gauge shell exploded. The brass burned in there is from the side wall of the twenty-gauge shell. Court: Mr. King, are you expressing your opinion from your examination of that, or from what you heard and also from your examination of that barrel? A. I am expressing my opinion from the examination of that barrel, and many tests I have made with barrels, and produced exactly similar bursts. I have a barrel of a twelve-gauge gun that I have tested in that manner, at the hotel. I didn’t bring it to the court with me. I have made tests as to the overloaded shells with extra large quantities of powder or explosives. In my opinion an extra heavy loaded shell would not have caused a gun to burst at that point. It would burst in the breach, in the chamber. Right here, where the load would be chambered; it would tear the chamber up. It might extend forward and will not be confined to that point. It might tear the barrel so badly as to extend further forward than the exact length of the chamber. The result on the empty shell of such an explosion, made with high pressure shells, would tear the shell apart. Q. Please state if, in your opinion, an extra heavily loaded gun shell would cause a burst like that. A. No, sir. (Court: He has already testified to that.) A. The bulge I spoke of is always caused by an obstruction. 'When there is an obstruction in the gun barrel, the load being driven up to the obstruction is momentarily held up, which causes extra high pressure, and causes a ring, or bulge. The length of the chamber in that gun, for the explosion of the shell, is slightly over two and five-eighths inches long, and these Nitro Club scatter load shells are a fraction longer than this chamber, as they are two and three-quarters. The effect of using that kind of shell in a gun of a short chamber is that it tends toward raising the breach pressure somewhat.” To the material portions of the testimony of the expert, King, above set forth, plaintiff excepted and assigned error. We think the testimony was competent. On cross-examination he testified, in part: “I say there is brass there, a very small particle, big as a pin head. I would not say how much larger. Q. You are sure that is not rust? A. I am sure it is brass. . . . Q. If the jury found this shell came out of there, you would say, in your expert opinion, this shell didn’t blow this gun open, would you? A. If I knew that shell did come out of that chamber, and I knew that shell had been fired? Q. Yes? A. No, but I would say the twenty-gauge ahead of that shell did it. Q. You mean the difference in the calibre?- A. A loaded twenty-gauge shell was in that barrel, and assuming that was the shell that was fired, when these shells were fired and exploded, the twenty-gauge caused the damage. Q. You mean there *807were two shells in there? A. Yes, sir. Q. You base your expert opinion on that? A. Yes, sir.” The same testimony appears in the record elicited by plaintiff. Albritton v. Albritton, ante, 111 (114). The testimony of the expert, King, was admissible in evidence, the probative force w-as for the jury to determine.

Shaw v. Handle Co., 188 N. C., 222, was tried by Devin, J., when he ivas on the Superior Court bench, and he permitted a physician, an expert, to testify on personal knowledge, observation, etc., as to the cause of the death of two men found dead in a closed gasoline boat — that it was carbon monoxide gas. At p. 232, this Court said: “Dr. Garriss saw the boat, the condition of the two men, how they were lying, the windows down, and, by personal observation, had knowledge of the entire situation. With this personal knowledge and observation of all the facts, and Dr. Garriss’ training and experience as a physician, we think this evidence competent. Its probative force was for the jury,” citing Flaherty v. Scranton Gas and Water Co., 30 Pa. Superior Court Rep., 446. “In that case (Flaherty case, supra), nor in the case at bar, was there an autopsy. The examination in each case was external and all the surrounding facts known to the physicians. They knew the facts, and on the known facts gave their opinion. Their education and training were for the purpose of enabling them to deal with and express their opinion as to what ills and the causes that constantly threaten and affect humanity. In Davenport v. R. R., 148 N. C., 294, Hoke, J., says: ‘Even if it should be regarded as more strictly “opinion evidence,” when it comes from a source of this kind, from one who has had personal observation of the facts, and from practical training and experience is qualified to give an opinion which is likely to aid the jury to a correct conclusion, such evidence is coming to be more and more received in trials before the jury. McKelvey speaks of it with approval as “expert testimony on the facts.” McKelvey, p. 230.’ S. v. Morgan, 95 N. C., 641; Jones v. Warehouse Co., 137 N. C., 337; Jones v. Warehouse Co., 138 N. C., 546; Lynch v. Mfg. Co., 167 N. C., 98; Ferebee v. R. R., 167 N. C., 290. . . . The evidence in Summerlin v. R. R., 133 N. C., p. 551, was excluded in the lower court, and sustained, ‘upon the ground that the witness was called upon to state a fact of which he had no personal or competent knowledge, and not merely the opinion of an expert. The opinion of the witness should be based upon facts admitted or found, or upon his personal knowledge, and not upon the assumption of the fact. The question should therefore be hypothetical, or rather supposititious, in form, following the precedents as settled in our decisions.’ Mule Co. v. R. R., 160 N. C., 252; Hill v. R. R., 186 N. C., 475.” S. v. Hightower, 187 N. C., 300 (307); S. v. Fox, 197 N. C., 478 (486); Dempster v. Fite, 203 N. C., 697 (706-7); Green v. Casualty Co., 203 N. C., 767 *808(772); S. v. Atlantic Ice & Coal Co., ante, 742. From tbe view we take of this case, we see no error in the charge of the court below.

The facts and circumstances on which the expert based his opinion were practically uncontroverted. Perhaps Emerson’s testimony indirectly corroborated the expert’s opinion. The plaintiff testified there v*as nothing in the barrel when he put the shell in, yet his companion, Emerson, who was shooting a 20-gauge and plaintiff a 12-gauge shell, testified that he took plaintiff’s gun out of the case and was looking at it and was under the impression that he broke it, but could not say definitely. He never ,said that he did not put the 20-gauge shell in the plaintiff’s gun. It may be that he unthoughtedly put the 20-gauge shell in it. This was a legitimate circumstance for the jury to consider. This was a fact within the witness’ knowledge.

For the reasons given, we find

No error.